ij vuqj+{k.k iqfLrdk...Coded Audio frequency track circuit 4.1 ifjp; Introduction 1 4.2 oxhZdj.k Classification 2 4.3 rdfudh vkadMs Technical data 2 4.4 iz.kkyh dh jpuk System composition

Hkkjr ljdkj GOVERNMENT OF INDIA jsy ea=ky; MINISTRY OF RAILWAYS

vkWfM;ks fÝDosalh VªSd lfdZV

ij vuqj+{k.k iqfLrdk

MAINTENANCE HANDBOOK ON

AUDIO FREQUENCY TRACK CIRCUIT

dSeVsd@,l@izkStsDV@2013&14@,pch&, ,Q Vhlh@2-0 CAMTECH/S/PROJ/2013-14/HB-AFTC.2.0

ebZ 2013 MAY 2013

egkjktiqj] Xokfy;j & 474005

MAHARAJPUR, GWALIOR – 474 005

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FOREWORD

Track circuits detect presence of train vehicles on different portions of track and hence play a vital role in signalling. Audio Frequency Track Circuit is one of such types which has its own advantages. Audio Frequency Track Circuits have been installed on various stations as well as sections of Indian Railways including Intermediate Block Signalling and Automatic Signalling sections.

CAMTECH is continuously making efforts in documentation and upgradation of information on advanced maintenance practices. This handbook prepared on the subject is a step further in this direction. I hope that this handbook will be helpful for the signal maintenance personnel in updating their knowledge and maintaining the system.

CAMTECH Gwalior A.R.Tupe Date: Executive Director

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dSeVsd] Xokfy;j fn-dq-;kno fnukad 31-5-2013 la- funs’kd¼ladsr ,oa nwj-½

PREFACE

The joint-less Audio Frequency Track Circuits have several advantages over conventional track circuits and these are unaffected by the interference due to traction harmonics in electrified area. AFTCs have applications in straight sections and point zones of Station area as well as in proving of Block section including Automatic Signalling section.

This handbook has been prepared to help the field personnel in efficiently maintaining Audio Frequency Track Circuits installed in their section. Apart from general overview, installation guidelines, maintenance instructions and do’s & don’ts the handbook also covers sections containing information on AFTCs of RDSO approved manufacturers.

It is clarified that this handbook does not supersede any existing provisions laid down in Signal Engineering Manual, Railway Board publications and RDSO publications. This handbook is not statutory and instructions given in it are for the purpose of guidance only.

We are sincerely thankful to Shri Nirala Katiyar, Sr.D.S.T.E./Sig/New Delhi/Northern Railway., M/s Alstom, M/s Siemens, M/s Bombardier, M/s Ansaldo and field personnel who helped us in preparation of the handbook.

Since technological upgradation and learning is a continuous process, you may feel the need for some addition/modification in this handbook. If so, please feel free to give your comments on email address [email protected] or write to us at Indian Railways Centre for Advanced Maintenance Technology, In front of Adityaz Hotel, Airport Road, Maharajpur, Gwalior (M.P.) 474005.

CAMTECH Gwalior D.K.M.Yadav Date: Jt .Director (S&T)

CONTENTS

vuqHkkx Section

fooj.k Description Page No.

izkDdFku Foreword IV Hkwfedk Preface VI fo"k; lwph Contents VIII lq/kkj iphZ Correction Slip X fMLDySej Disclaimer XII I vkWfM;ks fÝDosalh Vªsd lfdZV Audio frequency track circuit 1.1 ifjp; Introduction 1 1.2 ykHk Advantages 1 1.3 eq[; Hkkx Main modules 1 1.4 fofHkUu Hkkxksa ds dk;Z Functions of various modules 2 1.5 bySDVªhdy lsijs’ku TokbZaV Electrical Separation Joint

(ESJ) 3

1.6 vksojySi tksu Overlap Zone 4 1.7 ,,QVhlh dk oxhZdj.k Classification of AFTC 4 1.8 ,,QVhlh ds foU;kl Configurations of AFTC 5 1.9 dk;Z ds fl/kkar Principle of working 5 1.10 vkjMh,lvks }kjk vuqeksfnr QesZa RDSO approved firms 6 II laLFkkiuk Installation 2.1 Ikfjp; Introduction 1 2.2 laLFkkiu gsrq lkekU; vuqns’k General installation guidelines 1 2.3 ,,QVhlh dh lhek ij VªSD’ku

fjVuZ rFkk ØkWflax ckWf.Mx Traction return and cross-bonding at termination of AFTC

2

2.4 ÝhDoaslh vyksds’ku Iyku rS;kj djuk

Preparation of Frequency allocation plan

4

2.5 dscy dksj Iyku rS;kj djuk Preparation of Cable Core plan 4 2.6 dscyksa dk ifj{k.k Testing of Cables 4 2.7 vkarfjd laLFkkiu Indoor installation 4 2.8 ckgjh laLFkkiu Outdoor installation 5

III , chch Vh 1&12 vkWfM;ks fÝDosalh Vªsd lfdZV

ABB T1-21 Audio Frequency Track Circuit

3.1 ifjp; Introduction 1 3.2 eq[; Hkkx System Composition 1 3.3 fÝDosalh ds vkcaVu dh ;kstuk Frequency allocation plan 3 3.4 rdfudh vkadMs Technical data 3 3.5 dscy fcNkus dh ;kstuk Cabling scheme 4 3.6 laLFkkiu gsrq funsZ’k Installation guidelines 4 3.7 ifj{k.k ,oa dk;kZfUor djuk Testing and commissioning 5 3.8 ,,QVhlh midj.kks dk

lek;kstu Adjustment of AFTC equipment 7

vuqHkkx Section


3.9 vuqj{k.k rFkk fujh{k.k Maintenance & Inspections 8 3.10 =qfV ds y{k.k rFkk fuokj.k Fault diagnosis and rectification 8 3.11 vko';d vkStkj @ midj.k Tools/Equipments required 9

IV lhesal ,QVhth ,l fjeksV QsM dksMsM vkWfM;ks fÝDosalh Vªsd lfdZV

Siemens FTG-S Remote- fed, Coded Audio frequency track circuit

4.1 ifjp; Introduction 1 4.2 oxhZdj.k Classification 2 4.3 rdfudh vkadMs Technical data 2 4.4 iz.kkyh dh jpuk System composition 3 4.5 dscy fcNkus gsrq ;kstuk Cabling scheme 7 4.6 VªSd ls la;kstu Track side connections 7 4.7 fÝDosalh o MkVk dksfMax dk

vkcaVu Frequency and data coding allocation

9

4.8 fÝDosalh rFkk fcV iSVuZ ¼MkVk½ dksfMax Iyx

Frequency and bit pattern (Data) coding plugs

9

4.9 iSjkehVj ntZ djuk Recording of parameters 10 4.10 vuqj{k.k Maintenance 10 4.11 ekud ywihax o xsy lsfVax Standard looping and gain

setting 12

4.12 vkStkj o ekius ds midj.k Tools and measuring equipment

13

=qfV;ks ds y{k.k @ ,ybZMh ladsrks ds fofHkUu Øe

Fault diagnosis /LED indicator combinations

14-17

V vYLVkWe fMft dksM vkWfM;ks

fÝDosalh Vªsd lfdZV Alstom DIGI CODE Audio Frequency Track Circuit

5.1 ifjp; Introduction 1 5.2 oxhZdj.k Classification 1 5.3 iz.kkyh dh jpuk System description 2 5.4 dscy fcNkus gsrq ;kstuk Cabling scheme 4 5.5 rdfudh vkadMs Technical data 4 5.6 fMft dksM ds dkMksZ dh tkudkjh Cards information 5 5.7 ,ybZMh ladsr ,oa ijh{k.k fcanq LED indications and testing

points 6

5.8 vuqj{k.k Maintenance 9 5.9 =qfV;ksa ds y{k.k Fault diagnosis 11 5.10 VwyfdV Tool kit 12 5.11 =qfV fuokj.k gsrq ¶ykspkVZ Troubleshooting Flowcharts 14-15 =qfV;ks ds y{k.k @ ,ybZMh

ladsrks ds fofHkUu Øe Fault diagnosis /LED indicator combinations

16-21

vuqHkkx Section


VI vulkYMks ;w ,e 71 vkWfM;ks fÝDosalh Vªsd lfdZV

Ansaldo UM71 Audio Frequency Track Circuit

6.1 ifjp; Introduction 1 6.2 iz.kkyh dh jpuk System composition 1 6.3 dscy fcNkus gsrq ;kstuk Cabling scheme 5 6.4 rdfudh vkadMs Technical data 5 6.5 xsu lasfVax Gain setting 6 6.6 vuqj{k.k Maintenance 9

VII fuokjd vuqj{k.k Preventive Maintenance 7.1 vuqj{k.k gsrq tkap Maintenance checks 1 7.2 cká 'kaV }kjk ijh{k.k Testing with external shunt 2 7.3 vuqj{k.k ds le; lko/kkfu;ka Precautions during

maintenance 3

VIII D;k djsa o D;k u djsa Do’s & Don’ts

8.1 D;k djsa Do’s 1 8.2 D;k u djsa Don’ts 1

IX Ckgq/kk iwaNs tkus okys iz’u Frequently Asked Questions 1-2

Annex. I laf{kIr 'kCnkoyh Abbreviations

Annex. II lanHkZ References

ISSUE OF CORRECTION SLIPS

The correction slips to be issued in future for this handbook will be numbered as follows:

CAMTECH/S/PROJ/2013-14/HB-AFTC/2.0# XX date .......

Where “XX” is the serial number of the concerned correction slip (starting from 01 onwards).

CORRECTION SLIPS ISSUED

Sr. No. of Correction

Slip

Date of issue

Page no. and Item No. modified

Remarks

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izdk'kuks rFkk v-vk-eka-l- ds ekxZn'kZu ;k tksuy jsYos ds funsZ'kksa dk ikyu djsaA

DISCLAIMER

It is clarified that the information given in this handbook does not supersede any

existing provisions laid down in the Signal Engineering Manual, Railway Board and

RDSO publications. This document is not statuary and instructions given are for

the purpose of guidance only. If at any point contradiction is observed, then SEM,

Railway Board/RDSO guidelines may be referred or prevalent Zonal Railways

instructions may be followed.

----------------------------------------------------------------------------------------------------

If you have any suggestion & any specific comments, please write to us:

Contact person : Director (Signal & Telecommunication)

Postal Address : Centre for Advanced Maintenance Technology, Maharajpur,

Gwalior (M.P.) Pin Code – 474 005

Phone : 0751 - 2470185

Fax : 0751 – 2470841

Email : [email protected]

CAMTECH/S/Proj/2013-14/HB-AFTC/2. 0

Section I – Audio Frequency Track Circuit May 2013

1

Section I

vkWfM;ks fÝDosalh Vªsd lfdZV AUDIO FREQUENCY TRACK CIRCUIT

1.1 ifjp; Introduction

Conventional Track circuits have been found to be affected by the high levels of interference due to traction harmonics present in AC or DC electrified areas. The joint-less Audio Frequency Track Circuit (AFTC) is the solution in such sections since they are immune to above interferences. The AFTC works with modulated signal in audio frequency range and its extremities are defined electrically by the use of tuned circuit techniques. AFTC conforms to IRS specification no.RDSO/SPN/146/2001.

1.2 ykHk Advantages AFTC can be universally used in AC, DC and Non-RE sections.

Electrical separation joints define AFTC geographical boundaries.

No insulation joint is required except in point zone where adjacent AFTC is from

different manufacturer or type of track circuit changes. Thus dependency on other

departments is minimized.

AFTC has built-in time delay for picking up its relay hence separate slow to pick

up TPR is not required.

Not affected by harmonics generated by Thyristor controlled locomotives as it

uses FSK/MSK principle for signal transmission.

Both rails are available for traction return current.

Suitable for longer length track circuits.

Suitable for IB and Automatic Signalling section.

Added safety with modulation (coding).

Remote feeding upto 3 km possible.

1.3 eq[; Hkkx Main modules

The Audio Frequency Track Circuit system consists of following modules: Table I



2

1.4 fofHkUu Hkkxksa ds dk;Z Functions of various modules

(a) Transmitter (Tx) Transmitter generates and modulates audio frequency according to a scheme planned along with the receiver.

(b) Track Tuning Unit (TTU) The electrical separation of adjacent track circuits is obtained by tuning a short length

of track (about 20 metres) using tuning units. Each tuning unit offers low impedance to the frequency of adjacent track circuit and prevents its influence.

(c) End Termination Unit (ETU) It is used at the start and the end of section provided with AFTC. It is also used in place of TTU for Centre fed arrangement or when the adjacent track circuit is of other type or of different manufacturer. An insulated rail joint is normally provided beyond the ETU within one metre.

(d) Receiver (Rx)

The receiver receives the correct track circuit signal via tuning unit and recognizes it in quality (modulation or bit pattern) and in quantity (level or amplitude) and operates the output relay accordingly. More than one receiver may be required for point zone track circuit.

(e) Power Supply Unit A common power supply unit generally feeds Transmitter and Receiver of two adjacent AF Track Circuits. [Input230V/110V (nominal) 50 Hz ± 2.5 Hz single-phase AC and gives output of 24 V DC]

(f) Leads/Connections and fastening to rails

For connecting Track Tuning Unit with Tx or Rx, Signalling cable or 6 quad cable (0.9 sq.mm dia) is used. For connection of Tuning Unit to track, thick cable of 25 sq.mm dia. conductor (Aluminium or Copper) is used.

(g) Rail Bonds Imbalance in traction return current associated with rails in both 25 KV AC traction and 1500 V DC traction may cause damage to the AFTC equipment. To avoid this different types of bonds are provided depending upon the configuration of AFTC.

Sr. No.

Description Location

1. Transmitter (Tx) 1 No. 2. Receiver (Rx) 1 No. 3. Trackside Tuning Units (TU) 2 Nos., one at Tx end and other at Rx end 4. Power Supply unit 2 Nos., one at Tx end and other at Rx end 5. Output relay 1 No., at Rx end 6. Leads/Connections and fastening to rails At both ends 7. Rail Bonds At both ends8. Surge arrester 2 Nos., one for each tuning unit.



3

(i) S bonds These are used in straight track circuit between two consecutive AFTCs of same

manufacturer. This consists of two semi-loops each delimited between its centre tap and its connection point to the rail. The farther semi-loop of the S-bond is tuned to the operating frequency of track circuit. The other semi-loop is tuned to the operating frequency of neighbouring track circuit. An axle standing on the S-bond occupies both the near and advance track circuits thus causing overlapping of the two track circuits so that there is no detection gap. Fig.1.1 (a): S – bond

(ii) End bonds or Alpha bonds (Termination bonds) These are used in the end of the track circuit as terminal bond. These are provided along with insulation joint for separating AFTC with other type of track circuit (Conventional DC/AC track circuit) or AFTC of other manufacturer. For traction return current the center of alpha bond to be connected to next DC/AC track circuit or AFTC of other make. Fig.1.1 (b): Alpha bond

(iii)Shunt bonds These are provided at the termination of AFTC whose adjacent section is non-track circuited (End of AFTC). Only insulation joints are provided for separating two AFTCs in point zone track circuits, if enough space is not available. S-bonds can be provided if enough space is available. Fig.1.1 (c): Shunt bonds

(h)Relay

Relay used shall be DC neutral line relay conforming to either specification no BRS 930A or K-50 type depending upon design.

(i)Surge arrester

The equipment is suitably protected against atmospheric voltage surges by provision of surge arrestor between tuning unit and Transmitter/Receiver in order to limit the harmful effects of lightning.

1.5 bySDVªhdy lsijs’ku TokbZaV Electrical Separation Joint (ESJ) Electrical isolation between two adjacent AFTCs consists of a rail bond and a tuning

unit. The tuning unit is located in the trackside connection box and used to tune the electrical joint to the relevant track circuit frequency.



4

In the Fig.1.2 below, TU of

frequency f3 offers high impedance to its own track circuit frequency f3 and low impedance (zero) to the adjacent track circuit frequency f5 and vice-versa.

Thus electrical isolation is

formed between these two track circuits.

Fig.1.2: Electrical Separation Joint Tuned Zone

The tuned zone comprises a measured length of track which is used for forming ESJ.

1.6 vksojySi tksu Overlap Zone Overlap zone is the portion of tuned zone in which both the AFTC Relays drop when it is shunted by 0.15 Ohms resistance. Examples are given below.

Fig. 1.3 : Two adjacent AFTCs DT1 & DT2

A =Non-shunting zone of track circuit DT-2

B = Non-shunting zone of track circuit DT-1

C = Shunting zone of track circuit DT-1 and DT-2(Overlap zone)

1.7 ,,QVhlh dk oxhZdj.k Classification of AFTC

(a)As per type of modulating signal (i)Non-coded In this type of AFTC, the modulating signal is not coded.

(ii)Coded In this type of AFTC, the modulating signal is bit coded with digital message.



5

As bit coding of modulating signal enhances the safety, coded type track circuits are preferred over the non-coded type. (b)As per feeding arrangement (i)Locally fed In this arrangement, Tx, Rx, Power supplies to Tx and Rx and relay are kept in trackside location boxes. Track repeater relay is only kept at relay room. (ii)Remote fed In this arrangement, Tx, Rx, Power supplies to Tx and Rx and relay, all equipments are kept centrally in AFTC room, while tuning units are kept in trackside location boxes.

1.8 ,,QVhlh ds foU;kl Configurations of AFTC

AFTC can be configured in two ways (i) End fed In this configuration, Transmitter is provided at one end and Receiver is provided at the other end. (i)Centre fed Centre fed arrangement is provided when longer length of track circuit is used say beyond 900 mtrs. Tx is provided at the centre of the track circuit, while Rx is installed at both the ends of the track circuit.

1.9 dk;Z ds fl/kkar Principle of working

AFTC works on Frequency Shift Keying (FSK) technique, where the carrier frequency is shifted between two frequencies close to each other. The basic carrier frequency (Audio Frequency) and the modulating frequency are generated by the Transmitter. Carrier frequency and the modulating signal (Digital data) are fed to the FSK modulator which generates output of higher frequencies and lower frequencies with reference to modulating (Digital data) signal. The modulated output signal after amplification and filtering is fed to the track through tuning unit which forms a resonant R-L-C circuit along with connected rails and bonds for the corresponding frequency band. Audio Frequency voltage (AC) is fed to the track and a portion of track thus tuned to a frequency receives maximum power from transmitter. The signal transmitted through the rails is received by the receiver unit. The receiver is tuned to the corresponding frequency through tuning unit. The resonant R-L-C circuit formed by rails, bonds and tuning unit delivers maximum power to the receiver. The output from tuning unit is extended to a relay driver after amplification, filtering and demodulation in the receiver. The output of relay drive operates a 50 volt line relay conforming to BRS 930A or K-50 relay when voltage with sufficient amplitude within prescribed frequency range is received.



6

The basic carrier frequency for each track circuit in a station shall be different from adjacent track circuit to avoid mutual interference.

Fig.1.4: Block diagram for AFTC

1.10 vkjMh,lvks }kjk vuqeksfnr QesZa RDSO approved firms Following are the RDSO approved firms for the manufacture, supply and installation of AFTC on Indian Railways: (i) For Coded type 1. M/s Alstom Projects India Ltd.., No.63, Trichy Road, Kannamapalayam Post,

Coimbatore -641 402. 2. M/s Siemens Ltd., Mobility Division, R&D and Technology Centre, Kalwa Works,

Thane-Belapur Road, Airoli Node, Navi Mumbai – 400 708. (ii) For Non-coded type 1. M/s Bombardier Transportation India Ltd., Bombardier House, Race Course Circle,

Vadodara – 390 007. 2. M/s Ansaldo STS Transportation Systems India Pvt. Ltd., 35, SLV Complex, AVS

Compound, 80 feet Road, Koramangla, IV Block, Bangalore – 560 034.


Section II – Installation May 2013

1

Section II laLFkkiuk

INSTALLATION

2.1 Ikfjp; Introduction In this section, installation guidelines which are common to all types of AFTC have been given. If there is any deviation for AFTC of a particular manufacturer, the same have been given separately in the respective section.

2.2 laLFkkiu gsrq lkekU; vuqns’k General installation guidelines Installation of AFTC is to be done as per installation manual of OEM (Original Equipment Manufacturer) by qualified engineers of OEM or approved agency. Safety tests as specified by the manufacturers like Directionality test for S bonds, Interference test, TSR tests and proper track circuit adjustment should invariably be ensured and recorded before commissioning. Provision of liners and pads under both the rails, proper drainage to avoid water logging in the track, clearance of foot of the rails from ballast etc. are to be ensured. As AFTC is inherently a double rail track circuit, it is recommended that bonding practice should be adopted as per provisions of ACTM for Double Rail track circuits. Tuning zone must not contain check / guard rails, level crossing, catch point / expansion joint, TPWS (or AWS) track equipment, impedance bonds, old bypassed insulated rail joints and structure bond / cross bond. Maximum permissible cable lengths between Transmitter (TX) & its TU (Tuning Unit) and Receiver (Rx) & its TU with 0.9 mm dia. copper conductor of quad cable shall be within specified limits as per the technical and installation manuals of AFTC. TX and Rx of same track circuits should not run in one cable. Receivers of different track circuits having same frequency should not run in one cable. Similarly, Transmitters of different track circuits having same frequency should not run in one cable. Cable compensating resistance, line matching unit, end terminating unit, approved type equi-potential /S / Alpha/ Shunt bond etc. shall be used as applicable. As design of AFTC is specific to make, it would be preferable not to install variety of AFTCs in a section from maintenance point of view. At boundary of AFTC of one make with another make or DC track circuit, specified arrangement as per AFTC’s technical and installation manuals should be provided and continuity of traction return current path should be ensured and strengthened. General guidelines in this regards are given in para 2.3 below.



2

2.3 ,,QVhlh dh lhek ij VªSD’ku fjVuZ rFkk ØkWflax ckWf.Mx Traction return and cross-

bonding at termination of AFTC

2.3.1Termination with non-track circuited portion A shunt bond is provided at the termination.

Fig2.1: Termination of AFTC with non-track circuited portion

2.3.2 DC Traction Area (a) Termination with conventional AC Track Circuit

A pair of insulation joints and impedance bond at the termination are provided.

Fig.2.2: Termination with conventional AC Track Circuit (b) Termination with AFTC of other manufacturer A pair of insulation joints and back to back alpha bonds at the termination are provided.



3

Fig.2.3: Termination with AFTC of other manufacturer (c) Return path of sub-station and parallel tracks

The traction return path is provided through DC impedance bond of suitable capacity. Connection either to power substation or to parallel tracks is realized through the center tap of impedance bonds.

Fig.2.4: Return path of sub-station and parallel tracks

2.3.3 AC Traction Area

(a) Termination with conventional DC Track Circuit A pair of insulation joints are provided at the termination and the traction return path is provided through Terminal bonds shown in Fig. below.:

Fig.2.5: Termination with conventional DC Track Circuit

(b) Termination with AFTC of other manufacturer A pair of insulation joints and back to back Alpha bonds are provided.



4

Fig.2.6: Termination with AFTC of other manufacturer

Note: The traction return path is provided through centre tap of terminal (Alpha) bonds.

2.4 ÝhDoaslh vyksds’ku Iyku rS;kj djuk Preparation of Frequency allocation plan The railway has to prepare frequency allocation plan and installation plans jointly with the OEM. The Frequency allocation plan is based on the approved Interlocking Plan (I.P.) and lists out Frequency distribution, Track Circuit name, Track Circuit Length, Bit code (For coded type AFTC) and Electric Joint layout. AFTCs of different frequencies are to be installed alternatively as per Frequency allocation plan.

2.5 dscy dksj Iyku rS;kj djuk Preparation of Cable Core plan The Cable Core Plan lists out Quad cable distribution from Relay Room to Outdoor equipment. Separate quad cable should be used for Transmitter & Receiver irrespective of main and tail cable. Armours of each quad cable to be earthed at location boxes and at the tuning unit.

2.6 dscyksa dk ifj{k.k Testing of Cables Minimum Insulation resistance between each pair at CT Rack should be more than 10 mega Ohms/Km. Loop resistance of each pair should be recorded and maintained separately. It shall be maximum resistance of 56 Ohm/Km at 20 deg C.

2.7 vkarfjd laLFkkiu Indoor installation Indoor Installation mainly involves erection of main rack and configuration of sub assembly in the main rack.



5

Fig. 2.7: A typical AFTC indoor wiring plan

Erection of Main Equipment rack. Rack Arrangement Plan: It describes AFTC equipment rack arrangement with

Track Circuit distribution in each rack. Assembly of Sub-rack in the main rack based on Rack Arrangement Plan. Power Wiring Relay Wiring Earthing & Surge protection

Note: If Tx, Rx and Power Supply units are installed in outdoor location box, then only

relay wiring is required in cabin/relay room. 2.8 ckgjh laLFkkiu Outdoor installation

Outdoor Installation mainly involves following items

Laying of Quad cable. Erection of Tuning Units. Laying of electric joint and completing the TU to Rail connections. Assembly of Tuning Unit in the Mounting stand Connection between TU and rails. Copper bush to be riveted in the rails before

making connection with rails. Cable Wiring. Finally the Tuning to be done in Tuning Units.



6

Fig. 2.8: A typical AFTC outdoor plan

2.8.1 Connection of 25 sq. mm copper cable from TU to rail

For connecting 25 sq. mm Copper cable to rail web:

Drill a hole of 19 sq. in the rail web.

Insert 12 mm Hex. Head Bolt.

Insert Copper bush and Rivet using Hydraulic tool.

Insert 25 Sq.mm Lug for connecting the cable.

Tighten with washers and nuts as shown in Fig. below

Fig.2.9: 25 sq. mm copper cable with lug



7

Fig 2.10.: Arrangement for connection of 25 sq. mm copper cable to rail

2.8.2 Connection of Electric joint to rail

For connection of electric joint (S-bond, Alpha bond or Shunt bonds) to rail web:

Drill a hole of 19 sq. in the rail web. Insert 12 mm Sq.Head Bolt .

Insert Copper bush and Rivet using Hydraulic tool. Insert 12 mm Square Head Bolt Tighten with washers and nuts as shown in Fig. below

Connect the electric joint cable using CAD-weld.



8

Fig.2.11: Arrangement for connection of Electric joint cable to rail

Fig.2.12: Connection of Electric joint cable to rail using CAD-Weld

After proper connection, AFTCs should be energized continuously before commissioning.


Section III - ABB T1-21 AFTC May 2013

1

Section III

, chch Vh 1&12 vkWfM;ks fÝDosalh Vªsd lfdZV ABB T1-21


3.1 ifjp; Introduction This system is non-coded type and operates on Frequency Shift Principle where the carrier frequency is shifted between two frequencies close to each other at the rate of modulating frequency (4.8 Hz). The carrier frequency is shifted by + 17 Hz into two frequencies at the rate of 4.8 Hz. Both these frequencies are detected independently and a number of other checks are performed to ensure safety against false operation. This gives a constant output only when both the frequencies are out of phase by 180 degrees. There are eight nominal frequencies (A to H) in the range of 1.5 KHz to 2.6 KHz which are employed to have eight types of track circuits as shown below. Any two types can be used per track and combination of all eight types can be used for quadruple lines.

Type Nominal Frequency

Actual Frequency band Lower Limit Upper Limit

A 1699 Hz 1682 Hz 1716 Hz B 2296 Hz 2279 Hz 2313 Hz C 1996 Hz 1979 Hz 2013 Hz D 2593 Hz 2576 Hz 2610 Hz E 1549 Hz 1566 Hz 1532 Hz F 2146 Hz 2163 Hz 2129 Hz G 1848 Hz 1865 Hz 1831 Hz H 2445 Hz 2462 Hz 2428 Hz

3.2 eq[; Hkkx Composition

The ABB-AFTC consists of Sr. No.

Description Quantity Description

1. Transmitter 1 Transmitter is connected to terminals 4 & 5 of TU for normal power mode and 1 & 2 for low power mode (short track circuits of 50 to 250 M)

2. Tuning Unit 2 Each TU present offers low impedance to the frequency of adjacent track circuit and prevents its influence

3. End Termination Unit

1

In centre fed TC and at the start & end of a section provided with AFTC. Two types of ETU – One with 3 parallel branches of circuits for frequencies A, C, E & G and other with two branches of circuits, for frequencies B, D, F & H



2

Sr. No.

Description Quantity Description

4. Receiver 1 Receiver is always connected to terminals 1 & 2 of TU

5. Power Supply Unit

2 A common power supply unit generally feeds two adjacent AF Track circuits.

6. Output Relay 1 50 V 1350 Ohm, DC neutral relay to BRS :930

Fig. 3.1: Transmitter Fig. 3.2: Receiver

Fig. 3.3: Power Supply Unit Fig. 3.4: Track Tuning Unit



3

3.3 fÝDosalh ds vkcaVu dh ;kstuk Frequency allocation plan Before installation of AFTC, a frequency allocation plan has to be prepared. In T1-21 type of AFTC there are eight operating frequencies. The allocation of frequencies is done as under: A&B – paired frequencies for first line C&D – paired frequencies for second line E&F – paired frequencies for third line G&H – paired frequencies for fourth line For more than four tracks the above sequence is repeated. There should be minimum separation of two lines, between track circuits of same frequency pair. On a continuously welded track (CWR/LWR), only one pair of the frequency should be used on any track, i.e. A/B, C/D, E/F or G/H. However, where insulated Rail joints are used, any combination of frequencies may be used.

3.4 rdfudh vkadMs Technical data

1. Power Supply Unit

Input (Nominal) 110 V AC 50 Hz Input tappings 5-0-95-105-115 V Output voltage 22.5 to 30.5 VDC Output current 4.4 A (Max.) Ripple 3V peak to peak

2. Track Circuit length

(a) End fed Low mode 50-250 meters Normal mode 200-650 meters

(b) Centre fed 450-1200 meters 3. Minimum ballast resistance 2 Ohm/Km 4. Minimum Train Shunt Resistance 0.5 Ohm (outside tuned area)

0.15 Ohm (inside tuned area) 5. Boundary of track circuit +/- 5 metres (max.) (from centre of tuned area) 6. Length of electrical separation joint 18.0 – 22.0 metres 7. Output relay 50 V/1350 Ohm, DC neutral relay to BRS:930 8. Current consumption of 24 V DC side Transmitter 2.2 A (Max.)

Receiver 0.5 A (Max.) 9. Transmitter power output (Max.) Low mode 3 W

Normal mode 40 W 10.

Maximum length of connecting cable between

(a) Transmitter & feed end tuning unit

30 metres

(b) Receiver & Receiver end tuning unit

350 metres

11.

Receiver output 40 – 65 V DC

12.

Maximum length of cable (19/1.8 Sq. mm Al.) between the tuning unit and track.

Long cable 3.25 M Short cable 1.45 M



4

3.5 dscy fcNkus dh ;kstuk Cabling scheme From cabin/relay room to outdoor location box - Quad cable - 0.9 mm dia From outdoor location box (Tx or Rx) to Tuning Unit – 36/0.3 mm twin copper cable. Lead wires from Tuning Unit to rail - 19/1.8 mm Aluminium cable using stainless steel nuts and bolts of M10 X L40 size and copper tinned lug of 96 sq.mm, M10 round type shall be used.

3.6 laLFkkiu gsrq funsZ’k Installation guidelines AFTC of different frequencies are installed alternatively as per frequency allocation plan. The units of the same frequency may be housed in the same location provided they are fed from separate power supply units. Tx, Rx, Power Supply Unit, Lightning arrestor and Relay should be fixed in a half/Full sized location box near the track as close as possible to the Tuning unit. The tuning unit should be fixed inside ME box, which can be mounted on stakes supported by a concrete foundation as close to rail as possible.

All the rails, except those having switch expansion joints and joints inside tuned area, in a track circuited portion shall be longitudinally bonded with the help of two 8 SWG GI wire. For bonding switch expansion joints and joints inside the tuned area 19/1.8 mm Aluminium cable using stainless steel nuts and bolts of M10 X L40 size and copper tinned lug of 96 sq. mm, M10 round type shall be used.

Fig.3.5: Installation of Tuning Unit

Fig.3.6: (a) Fixing arrangements (b) Channel pin used for connecting lead wire Power supply unit can be used to supply any combination of Tx and Rx provided its 4.4 Amp. rating is not exceeded and all Tx & Rx frequencies are different. On TU the Receiver is always connected to the terminal 1and 2, and the Transmitter is connected to the terminal 4 and 5. Terminal 3 must be earthed.



5

3.7 ifj{k.k ,oa dk;kZfUor djuk Testing and Commissioning Before commissioning, certain parameters are required to be checked using a special measuring instrument called Frequency Selective Meter (FSM) as shown below: Fig.3.7: Frequency Selective Test Meter

3.7.1 Transmitter/Receiver Input Voltage/Current Check Tx and Rx input supply voltage and current between terminals B24 and N24 of Tx and Rx. The voltage and current should be as below:

Fig.3.8: Measurement of Tx input voltage

3.7.2 Transmitter output and Transmitter Tuning Unit Input Voltage Check Tx output voltage at OP1 and OP2 and tuning unit input voltage at terminals 1&2/4&5 for low and normal mode respectively, using frequency selective meter unit.

The voltages should be as shown in Fig.3.9. Short Mod terminal with B24 and N24 of transmitter respectively and check upper and lower limits of carrier frequencies which should be as Track circuit frequencies.

Description Current Voltage (DC)

Transmitter Min.

Max.

Min. Max.

Low mode 0.2 A

0.4 A

22.5 A

30.5 A

Normal mode 1.3 A

2.2 A

22.5 A

30.5 A



6

Fig.3.9: Measurement of Tx output voltage

3.7.3 Transmitter and Receiver end Rail Voltage Check the Tx and Rx end rail voltage at terminals T1 and T2 of the respective tuning unit, by using frequency selective meter unit. Voltage should be as below:

Type of equipment Description A,C,E &G B,D,E &H

Min. Max. Min. Max. Transmitter Low mode 0.8 V AC 1.7 V AC 0.8 V AC 1.7 V AC Normal mode 4.5 V AC 5.3 V AC 5.8 V AC 6.6 V AC Receiver Low mode 0.5 V AC 0.9 V AC 0.5 V AC 0.9 V AC Normal mode 0.4 V AC 1.6 V AC 0.4 V AC 1.6 V AC

3.7.4 Transmitter/Receiver end Rail Voltage at companion tuning units Check Tx and Rx end companion tuning unit voltages at terminals T1 and T2, using frequency selective meter unit. AC voltage should be as below:

Type of equipment Description A,C,E &G B,D,E &H

Min. Max. Min. Max. Transmitter Low mode 70 mV 140 mV 0.8 V AC 1.7 V AC Normal mode 375 mV 440 mV 5.8 V AC 6.6 V AC Receiver Low mode 40 mV 75 mV 25 mV 50 mV Normal mode 30 mV 130 mV 20 mV 90 mV

Type Transmitter Tx. Tuning Unit

Output Voltage Input Voltage

Min. Max. Min. Max. A,C, E &G 10 V

AC 11 V AC

08 V AC

11 V AC

B,D,F&H 15 V AC

16 V AC

13 V AC

16 V AC



7

3.7.5 Receiver input current from Tuning Unit Measure the voltage across 1 ohm resistor connected in series with input of Rx.

3.7.6 Receiver output relay voltage Specified range 40 V to 65 V DC when relay is connected 120 V DC when relay is disconnected

3.8 ,,QVhlh midj.kks dk lek;kstu Adjustment of AFTC equipment After ensuring that the equipment has been installed and connected properly, set the power supply input tapping to match the 110 V AC and adjust the receiver gain as below:

3.8.1 Receiver gain table Track Circuit length (in metres) Input wiring & Pick up current

Normal mode Low mode Pick up current

Inputs Loop Loop Gain

Min. Max. Min. Max. 1 2 1 2 -- -- -- -- 195 mA 1H 1L 1 -- -- -- -- 98 mA 1L 3L 1H-3H 2

200 240 -- -- 65 mA 3H 3L 3 240 300 50 90 49 mA 1H 3I 1L-3H 4 300 360 90 110 39 mA 1L 9L 1H-3L 3H-9H 5 360 415 110 140 33 mA 3L 9L 3H-9H 6 415 475 140 170 28 mA 1H 9L 1L-3L 3H-9H 7 475 535 170 200 24 mA 1L 9L 1H-9H 8 535 595 200 230 22 mA 9H 9L 9 595 655 230 250 20 mA 1H 9L 1L-9H 10 655 710 -- -- 18 mA 1L 9L 1H-3H 3L-9H 11 710 770 -- -- 16 mA 3H 9L 3L-9H 12 770 1000 -- -- 15 mA 1H 9L 1L-3H 3L-9H 13

3.8.2 Procedure

(i) Put Tx on Normal mode Make proper communication arrangements between both ends. Connect 1 ohm Train Shunt Resistance (TSR) across rails at receiver end Tuning Unit (TU) and gradually go on reducing the gain till the relay drops.

Fig.3.10: Measurement of Rx input current from TU



8

Now increase the TSR to 1.1 Ohm, the relay should normally pickup. If it does not, then repeat the process with a TSR 1.2 and 1.3 Ohms. If the relay is still de-energised, increase the gain. Relay should now pick up. Reduce the TSR in steps of 0.1 Ohms. The relay must definitely drop out for TSR greater than or equal to 0.8 Ohms. (ii) Put Tx on Low mode Connect 1.5 Ohm TSR across Rails at Rx End Tuning Unit connections. Go on reducing the gain setting unless the relay drops. Now increase the TSR to 1.6 Ohm, the relay should pick up. If the relay does not pickup, repeat step 1 & 2 for TSR of 1.7 Ohms and 1.8 Ohms. Increase the gain if relay is still de-energised, now the relay should pick up. Reduce the TSR in steps of 0.1 Ohm. The relay should definitely drop out for TSR greater than or equal to 1.3 Ohm.

3.9 vuqj{k.k rFkk fujh{k.k Maintenance & Inspections (i) Fortnightly Ensure that the “Singing Noise” produced by the equipment is present. Measure the power supply output voltage and current. Measure the Transmitter output voltage. Measure the Reciever input current, if any adjustment is needed same shall be done as per para Measure the relay voltage. Inspect the track circuit connection with the rails and interconnections between power supply units, Tx, TUs, Rx and relay. Ensure that these are in order. Conduct shunt drop test with TSR of 0.5 Ohm outside the tuned area and 0.15 Ohm inside the tuned area. Note: Switch OFF the companion Tx sharing the tuned area under test, by removing fuse while measuring current/voltage of the equipment. (ii) Quarterly Check all nuts and bolts of tuning unit terminals and rail connection and ensure that these are fully tight. Check rail bonds. Check the lightning arrestor and its connection. Check the earthing of the equipment. Check the Transmitter upper and lower carrier frequencies.

3.10 =qfV ds y{k.k rFkk fuokj.k Fault diagnosis and rectification On failing both adjoining track circuits together, check power supplies, TU or interconnections. Always start checking from Tx end. Before starting a test, check TU to rail and impedance bond to rail connections.



9

(i) Transmitter end Check “Singing noise” produced by Tx and TU. If it is available then check Rail to Rail voltage at Tx end. Connect a 0.5 Ohm TSR across the feed end TU rail connections. If rail to rail voltage is reduced by 50% (approx.) then Tx end is OK. Check 24 V DC power supply and current to Tx and the Transmitter output voltage. If reading shows deviation from normal limit, the power supply unit, Tx or TU may be faulty. For integrity of interconnections, check I/P and O/P voltage of TU. If rail to rail voltage is not within normal limits, either TU or the rail connections may be faulty. If the Companion TU voltage is not within normal limit, Companion TU is faulty. In that case when T1 and T2 terminals of companion TU are shorted, the rail to rail voltage at the TU of the failed track circuit becomes OK. If Tx side is OK, patrol along the track checking bonds and insulation pads and metal burrs etc. (ii) Receiver end If voltage at Rx TU unit rail connections is low, either TU or connection has failed. If voltage at Companion TU is not within limit, it will be faulty. In that case if the rail to rail voltage at the TU of failed track circuit becomes OK when T1 and T2 terminals of Companion TU are shorted. If Rx input current is very less than operation current (15 mA), then the Rx TU is faulty. If Rx O/P is very less with a good power supply, change Rx. Check relay connections and the voltage on coil terminals, if not adequate change the relay.

3.11 vko';d vkStkj @ midj.k Tools/Equipments required Frequency Selective Meter Unit (FSMU) Multi Meter (Capacity -10 Amp.) Frequency Meter (0.1 Hz – 10 KHz) Shunt Resistance Box (0-2 Ohm in steps of 0.1 Ohm) Box and Flat Spanners of different size (M5, M8 & M10) Screw driver. Crimping tool


Section IV – Siemens FTG S AFTC May 2013

1

Section IV

lhesal ,QVhth ,l fjeksV QsM dksMsM vkWfM;ks fÝDosalh Vªsd lfdZV SIEMENS FTG-S REMOTE- FED, CODED

AUDIO FREQUENCY TRACK CIRCUIT 4.1 ifjp; Introduction

FTGS is a remote fed AFTC with a frequency modulated AC voltage in which data is coded into bits of odd and even streams. Audio frequency modulated (AC Voltage) and coded signals generated by the transmitter card are fed to the feed end track through a tuning unit and received at the receiver end tuning unit through rails. From receiver end T.U. the signals are sent to the receiver card provided in the cabin through telecom cables. Here the signals are demodulated and evaluated in two separate channels for redundancy. If the codes of received signal match with the preset code, two track relays, connected at the end of the channels in relay card (GF1, GF2) pick up. When the transmitted signal voltages get shunted through the vehicle axle, the two track relays (GF1,GF2) drop. Various LED indications are provided on each card to facilitate failure detection. Various testing voltage can be measured at measuring sockets.

Fig.4.1: Schematic diagram for Siemens FTG –S AFTC



2

4.2 oxhZdj.k Classification There are two types of track circuits with twelve operating frequencies and 15 bit patterns, to be provided within station limits and for outside the station limits. FTG-S 917 It is for shorter track circuits within station limits. Operates on frequencies 9.5 kHz to 16.5 kHz. i.e. total 8 frequencies with a difference of 1 kHz between consecutive frequencies. These have following variants: (i) Standard (ST)(65VA) (a) End fed (b) Straight line application (c) Lengths up to 350 m. (ii) Central feed-in (M) (75VA) (iii) Points (W) (75VA) - For Point zone with one turn out (iv) Crossing (KR) (85VA) - For Point zone with two turn out or crossing track circuit Operating frequencies are f1= 9.5 KHz, f2=10.5 KHz, f3=11.5 KHz, f4=12.5 KHz, f5=13.5 KHz., f6=14.5 KHz, f7=15.5 KHz, f8=16.5 KHz. FTG-S 46 These are provided for longer track circuits outside station limits. Operate on frequencies 4.75 to 6.25 kHz i.e. total 4 frequencies with a difference of 0.5 kHz between them. These have following variants: (i) Standard Configuration (ST) (80VA) (a) End fed (b) Straight line application (c) Lengths 350 m to 550 m (ii) Central feed-in (M) (90VA) (a) Centre fed (b) Straight line application (c) Lengths 550 m to 1000 m Operating frequencies are f9 = 4.75 KHz., f10=5.25 KHz, f11=5.75 KHz, f12=6.25 KHz. Adjacent sections and sections in parallel tracks are operated with different frequencies to prevent interaction.

4.3 rdfudh vkadMs Technical data

Minimum Ballast Resistance - 1.5 ohms/km (ideal is 2.5 ohms/Km) Maximum recommended TSR - 0.5 ohms (other than the tuned zone) Power Supply -(i) 230V AC + 10% -15%, 50Hz. + 2% Power Consumption: FTGS - 46 (i) Standard Configuration (ST) - 80VA (ii) Central feed-in (M) - 90VA

FTGS - 917 (i) Standard (ST) - 65VA (ii) Central feed-in (M) - 75VA (iii) Points (W) - 75VA

(iv) Crossing (KR) - 85VA



3

Minimum effective length of Track circuit - 30 M. Maximum effective length as per table below Table I Effective ranges for RB=1.5 Ohm X Km RB= 2.5 Ohm X Km FTG S 917 Remote

feeding Ps St 917 M 917 W/K

917 St 917 M 917

4.5 Km <= 1.0 Ohm 300 M 750 M YES 350 M 950 M 4.5 Km <=0.5 Ohm 350 M 850 M 400 M 1000 M 6.5 Km <= 0.5 Ohm 300 M 700 M 330 M 850 M

FTG S 46 Remote feeding

Ps ST 46 M 46 ST 46 M 46

6.5 Km <= 0.5 Ohm 600 M 1200 M 750 M 1500 M Ps = Permissible Train Shunt St = Standard Layout RB = Specific Ballast Resistance M = Centre-fed Layout W/K = Layout for Points and Crossings

4.4 iz.kkyh dh jpuk System composition

System consists of indoor equipment and outdoor equipment

4.4.1 Indoor Equipment It consists of two units - Evaluator and Power Supply Unit. (a) Evaluator This consists of a number of PCBs provided in one PCB frame mounted in a rack. In one rack, upto 10 FTG-S track circuit evaluators can be installed. Each evaluator is provided with a separate power supply unit. Front plate of the PCBs is equipped with LEDs for indication of operational data and easy diagnosis of failures. Measuring sockets are provided on each card to take readings and rectify the failures quickly. Types of evaluator FTG S 917 ST Evaluator FTG S 46 ST Evaluator FTG S 917 W Evaluator (For Point zone with one turn out) FTG S 917 KR Evaluator (For Point zone with two turn out or crossing track circuit) FTG S 46 M

Fig.4.2: FTG S 917 ST Evaluator



4

Fig.4.3: FTG S 46 ST Evaluator Evaluator consists of following plug-in type PCBs Frequency dependant cards (i) Amplifier and filter Card (No. S25533-B40 for FTGS 917)

Filter Card (No. S25533 –B42 for FTGS 46)

(ii) Receiver I Card (S25533-B33)

Fig.4.4: Amplifier & Filter card Due to the Frequency Filter in these cards, each frequency equipment has its own filter cards.

(i) Due to the multi-step input

filters in this card, each frequency requires its own special card.

(ii) Each receiver section has its own set of I L5, II L5, I L6 and II L6 LEDs.

Fig.4.5: Receiver I Card



5

Universal Cards (i) Transmitter Card (No.S25533-B30)

(ii) Demodulator Card (No. S25533 -B35)

v) Relay card (Card No. B36 A4)

Fig.4.7: Demodulator Card

This card can be used for any frequency/bit patterns by changing the two nos. of bit pattern coding plug (chips) on this card. LEDs I L7 and II L7 of the receiver-2 board S25533-B39-A3 only light up if all L5 and L6 LEDs of all associated receiver I and demodulator boards for channels I and II are also on.

This card can be used for any frequency/ bit pattern just by changing the frequency coding plug (chip) Fig.4.6: Transmitter card



6

(iii) Amplifier Card (No. S 25533-B41 for FTGS 46) This card can be used for all the frequencies of FTGS 46 type Track Circuits. (iv) Relay Card (No.S25533-B36) The relay board has a two-channel structure. Both channels are identical and each has a K50b metal to metal contact (2NC/2NO) signalling relay as an output relay. It has a pick up time of 600 milli sec and drop away time of 250 milli sec.

(v) Receiver II Card (Card No. B-39A for straight track) Two types of cards Receiver cards are available: No.S25533-B39 – Used for Standard (ST) configuration Track Circuits of any

Frequency/Bit pattern.

No. S25533 – B34 – Used for Point configuration (having Rx1, Rx2) and Centre Fed (M/W/KR) Track circuits of any Frequency/Bit pattern.

Fig.4.8: Receiver II Card (vi) Coding board The coding board S25533-B38-A1-*-4400 is required to program the mounting frames FTG S 917 W (S25533-C10-A2-*-4400) FTG S 46 M (S25533-C14-A3-*-4400). This board contains jumpers only. When using the mounting frames S25533-C10-A2-*- 4400 as a point track circuit or centre-fed track circuit, one coding board is required. When using the mounting frames S25533-C10-A2-*- 4400 as a standard track circuit, a second coding board is required. When using the mounting frames S25533-C14-A2 or –A3 -*- 4400 as a standard track circuit, one coding board is required.



7

(vii) Dummy Board Dependent on the board arrangement, not all the slots in the mounting frames are equipped with boards. Dummy boards must be used in these gaps as protection against accidental contact. (b) Power supply Unit

Each track circuit has its own power supply unit behind the associated mounting frame at the rear of the rack. Input voltage = 110V AC or 220 V AC Output voltage = + 5V DC, + 12 V DC

Fig 4.9: Power Supply Unit Front view

4.4.2 dscy fcNkus gsrq ;kstuk Outdoor Equipment Tuning units in track connection boxes - 2 Nos. Trackside connection box cables. - for connecting TU to rail. Rail bonds S-bonds, Shunt bonds, Termination bonds (Alpha bonds)

4.5 dscy fcNkus gsrq ;kstuk Cabling scheme From cabin to Tuning Unit – Star quad cable of 0.9 mm core diameter From Tuning Unit to rails - Copper ropes of diameter 25 sq mm Rail bonds (S, Alpha or Shunt) – 16 mm dia steel wire ropes

4.6 VªSd ls la;kstu Track side connections Transmitter TU

Cable from Relay room is connected to terminals 11&14. Track lead wires to rail is connected to terminals 9 & 10.

Receiver TU

Track lead wires from rail is connected to terminals 9 & 10. Cable to relay room is connected to terminals 15 & 20.

Measuring sockets



8

Fig.4.10: TX & Rx Tuning Units in a trackside connection box and termination

Fig. 4.11: Electrical separation joint with S-bond and actual connections at site



9

4.7 fÝDosalh o MkVk dksfMax dk vkcaVu Frequency and data coding allocation For adjacent track circuit, same frequency or the very next frequency should not be allotted. There should be a separation of at least one frequency with the exception of F8 and F9 since separation between these two frequencies is more. If same frequency is repeated anywhere in the same yard/centralized place then ‘data’ must be different for the other track circuit. Restrictions Frequency plan for more than two parallel tracks require interlacing of FTGS – 46 and FTGS – 917 AFTCs. FTGS-917 has limitation of 1 Km for remote feed against 2.9 Km for FTGS - 46 with 0.9 mm dia. copper conductor. For FTGS-917 to work for longer distance, 1.4 mm dia. copper conductor is required. AFTC in point zone requires insulation rail joints. FTGS-46 configuration cannot be used in point zone. FTGS -917 is permitted for point track circuit with two receivers.

4.8 fÝDosalh rFkk fcV iSVuZ ¼MkVk½ dksfMax Iyx Frequency and bit pattern (Data) coding

plugs Different frequency and bit pattern coding plugs are available to select the frequency and data in the transmitter card and also select the reference data signal in the demodulator card.

4.8.1Frequency coding plugs for Transmitter board only The transmitter board must be set to the defined frequency using a plug in accordance with S25533-A30-A1 to A12 -*- 4400 as given below:

Table II Variant Frequency Coding plug FTG-S 917 9.5 kHz S25533 – A30 –A1 - * - 4400

10.5 kHz S25533 – A30 –A2 - * - 4400 11.5 kHz S25533 – A30 –A3 - * - 4400 12.5 kHz S25533 – A30 –A4 - * - 4400 13.5 kHz S25533 – A30 –A5 - * - 4400 14.5 kHz S25533 – A30 –A6 - * - 4400 15.5 kHz S25533 – A30 –A7 - * - 4400 16.5 kHz S25533 – A30 –A8 - * - 4400

FTG –S 46 4.75 kHz S25533 – A30 –A9 - * - 4400 5.25 kHz S25533 – A30 –A10 - * - 4400 5.75 kHz S25533 – A30 –A11- * - 4400 6.25 kHz S25533 – A30 –A12- * - 4400

4.8.2 Bit pattern coding plug for Transmitter board and Demodulator board only

The predefined bit pattern must be set on the transmitter board using further plug in accordance with S25533-A30-A22 to A40 -*- 4400. The associated demodulator boards must each be equipped with two of the same plugs in accordance with S25533-A30-A22 to A40 -*- 4400 as given below



10

Table III Bit pattern

Coding plug Bit pattern

Coding plug

2.2 S25533 – A30 – A22- * - 4400 3.5 S25533 – A30 – A31- * - 4400 2.3 S25533 – A30 – A23- * - 4400 4.2 S25533 – A30 – A33- * - 4400 2.4 S25533 – A30 – A24- * - 4400 4.3 S25533 – A30 – A34- * - 4400 2.5 S25533 – A30 – A25- * - 4400 4.4 S25533 – A30 – A35- * - 4400 2.6 S25533 – A30 – A26- * - 4400 5.2 S25533 – A30 – A37- * - 4400 3.2 S25533 – A30 – A28- * - 4400 5.3 S25533 – A30 – A38- * - 4400 3.3 S25533 – A30 – A29- * - 4400 6.2 S25533 – A30 – A40- * - 4400 3.4 S25533 – A30 – A30- * - 4400

4.9 iSjkehVj ntZ djuk Recording of parameters The following readings should be taken during periodical maintenance (a) Power Supply Unit Input to PSU – AC Volts (110 V AC + 15% ) Output of PSU – DC Volts (12 V DC + 1 V) DC Volts (5 V DC + 0.5 V) (b) Readings at Tx end Frequency of AFTC – ……………KHz Input to Tuning Unit (Terminal No. 11 & 14) ……Volts AC (Audio Frequency Voltage) Output of Tuning Unit (Terminal No. 9 & 10) ……Volts AC Voltage across the rails……Volts AC (c) Readings at Rx end Voltage across the rails……Volts AC Input to Tuning Unit (Terminal No. 9 & 10) ……Volts AC (Audio Frequency Voltage) Output of Tuning Unit (Terminal No. 15 & 20) ……Volts AC. (d) Readings at Evaluator For troubleshooting the voltage readings at the power unit and measuring sockets provided on the evaluator can be taken. The permitted values are given in the table on next page.

4.10 vuqj{k.k Maintenance The boards of remote-fed audio frequency coded track circuits do not require any maintenance, because they do not have any moving parts with wear and tear.The reliable operation can be ensured by observing precautions and check points as given in Section VII.

4.10.1 Testing voltages at measuring sockets For troubleshooting purposes, the voltages at the power unit and measuring sockets of the major components can be measured. The permitted values are given in the table below:



11

Table IV Sr.No.

Card No.

Description Socket No.

Adjuster range

Permitted range

Actual reading (Sample data)

Remarks

1. B40/B41 Amplifier Input (Transmitter output)

1 & 2 20V AC 9 V to 12 V AC

(11.36 V)

Square wave voltage approx.18V T=1/10= 69 to 210 us

2. B33 12 V Supply voltage

I-8 & II-8 20 V DC 11 V to 13 V DC

(12.3 V)

3. B41 Amplifier Output

3.1 & 4.1 200 V AC 60 V to 90 V AC

(64.9 V) Square wave voltage approx.100 to 150V with peaks

4. B40/B42 Filter Card 3 & 4 200 V AC 30 V to 100 V AC

(73.3 V) To track (before cable stabilizing resistor)

5. B30 A2 Tx Card LEDs -- -- (L2 L3) Observe Flickering Frequency Code

6. B33 Rx I CH I Input

I-5 & II-8 20V AC > 6.5 V AC to < 20 V AC

(9 V ) With track clear

7. B33 Rx I CH II Input

II-5 & II-8

20V AC > 6.5 V AC to < 20 V AC

(9 V ) With track clear

8. B33 Rx I CH I Input

I-5 & II-8 20V AC < 5 V AC (2.16 V ) With track occupied

9. B33 Rx I CH II Input

II-5 & II-8

20V AC < 5 V AC (2.6 V) With track occupied

10. B33 Rx I CH I Output

I-6 & II-8 20V DC 12 V to 15 V DC

(14.16 V)

11. B33 Rx I CH II Output

II-6 & II-8

20V DC 12 V to 15 V DC

(14.24 V)

12. B33 Demodulator Input CH I

I-7 & II-8

20/2 V AC 1.3 V to 2 V AC

(1.73 V)

13. B33 Demodulator Input CH II

I-7 & II-8

20/2 V AC 1.3 V to 2 V AC

(1.8 V)

14. B39/34 Relay Voltage CH I

I-11 & I-12

20 V DC 16.5 + 1 V DC

(15.7 V)

15. B39/34 Relay Voltage CH II

II-11 & II-12

20 V DC 16.5 + 1 V DC

(15.7 V)



12

4.11 Standard looping and gain setting Voltage adjustment in Rx1 card Standard input to Rx I card is 0.3 V to 2 V AC. To achieve this, following looping is done in Rx unit: 3 -11 & 4 -13 – Low voltage 3 -12 & 4 - 13 – Medium voltage (Normal adjustment) 3 -11 & 4 - 12 – High voltage No voltage adjustment to be done in Transmitter T.U. Standard looping in Tuning unit Table V Type Looping FTGS 917 Tx 2 - 8, 7 – 8FTGS 917 Tx (without bond) Remove loop 7- 8, Remove GREY wire from terminal

9 and connect it to terminal 7 FTGS 917 Rx 2 - 8, 6 - 7, 3 - 11, 4 - 13 FTGS 917 Rx (without bond) Remove loop 6 - 7, Remove GREY wire from terminal

9 and connect it to terminal 7. FTGS 46 Tx No looping FTGS 46 Rx 3-11, 4-13 FTGS 46 Rx (without bond) (Centre fed)

Remove loop 7-9, Remove GREY wire from terminal 9 and connect it to terminal 7

Gain setting through DIP switches in RX1 card For gain setting, DIP switches are provided in the card numbered from 1 to 10. The following are the combinations of DIP switches to achieve different gain settings:

1 2 3 4 5 6 7 8 9 10 ON OFF OFF OFF OFF OFF OFF OFF OFF ON Highest Gain ON OFF OFF OFF OFF OFF OFF OFF ON OFF ON OFF OFF OFF OFF OFF OFF ON OFF OFF ON OFF OFF OFF OFF OFF ON OFF OFF OFF ON OFF OFF OFF OFF ON OFF OFF OFF OFF OFF ON OFF OFF OFF OFF OFF OFF OFF ON Normal Gain OFF OFF ON OFF OFF OFF OFF OFF OFF ON OFF ON OFF OFF OFF OFF OFF OFF ON OFF OFF OFF ON OFF OFF OFF OFF OFF ON OFF OFF ON OFF OFF OFF OFF OFF ON OFF OFF OFF OFF ON OFF OFF OFF OFF ON OFF OFF OFF ON OFF OFF OFF OFF ON OFF OFF OFF OFF OFF ON OFF OFF OFF ON OFF OFF OFF OFF ON OFF OFF OFF ON OFF OFF OFF OFF OFF OFF ON OFF OFF ON OFF OFF OFF OFF Lowest Gain

Fig. 4.12: Gain setting through DIP switches in RX1 card



13

4.12 vkStkj o ekius ds midj.k Tools and measuring equipment Outdoor equipment Frequency Selective Multimeter (Rishab 18S or similar) Resistor module (S25533 –A5 –A1 – contains 0.5 Ohm and 1 Ohm resistors for axle shunt simulation). Tuning module (S25533-A31-A1) 2 rail clamps (C25211 – A76-B3) Open-end, ring or box spanner, width across flats 13 mm. 3 mm. Allen key 3 mm screwdriver 3.5 X 0.5 mm. screwdriver (A2V00001156483) for WAGO terminals. Indoor equipment Frequency Selective Multimeter (Rishab 18S or similar) Adapter board (S25533 – B50 –A1) Potentiometer module (C25107 – A109 –A3) 1.5 mm screwdriver.



14

Fault diagnosis/LED indicator combinations

Table VI ○ – LED OFF ● – LED ON/Flickering Sr. No.

Power Unit

Transmitter (B30) Ampli-fier B41

Ampli-fier Filter B40-B42

Receiver I B33

Demo-dulator B35

Receiver II B39-B34

Relay module B36

Maintenance action required/Remarks

12V 5V L1 L2 L3 L8 L9 L4.1 L4 I L5

II L5

I L6

II L6

I L7

II L7

GF1 GF2

1 ○ ○ ● ● ● ● ● ● ● ● ● ● ● ● ● UP UP Section is clear (No action required)

2 ○ ○ ● ● ● ● ● ● ● ○ ○ ○ ○ ○ ○ DN DN Section is occupied or see no.12

3 ○ ○ ● ● ● ● ● ○ ○ ○ ○ ○ ○ ○ ○ DN DN Replace Amplifier Filter Module FTGS 917 (B40) or FTGS 46 (B41)

4 ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ DN DN Check voltages 110 V AC, 12 V DC, 5 v DC; if OK Replace Transmitter Module (B30)

5 ● ○ ○ ● ● ● ○ ○ ○ ○ ○ ○ ○ ○ ○ DN DN Check 12 V DC voltage 6 ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ DN DN Check 110 V AC Fuse 7 ○ ● ○ ○ ○ ○ ● ○ ○ ○ ○ ○ ○ ○ ○ DN DN Check 5 V DC voltage 8 ○ ○ ○ ● ● ● ● ○ ○ ○ ○ ○ ○ ○ ○ DN DN Replace Transmitter

Module (B30) 9 ○ ○ ● ○ ● ● ● ● ● ● ○ ○ ○ ○ ○ DN DN Replace Transmitter

Module (B30) 10 ○ ○ ● ● ○ ● ● ● ● ● ● ○ ○ ○ ○ DN DN Replace Transmitter



15

Sr. No.

Power Unit



Receiver I B33

Demo-dulator B35

Receiver II B39-B34

Relay module B36


12V 5V L1 L2 L3 L8 L9 L4.1 L4 I L5

II L5

I L6

II L6

I L7

II L7

GF1 GF2

Module (B30) 11 ○ ○ ● ● ● ● ● ● ○ ○ ○ ○ ○ ○ ○ DN DN Replace Amplifier

Filter Module FTGS 917 (B40) or FTGS 46 (B42). If fault persists, replace Transmitter Module (B30) as well

12 ○ ○ ● ● ● ● ● ● ● ○ ○ ○ ○ ○ ○ DN DN Check voltage between measuring sockets I 5 & II 8 on Receiver –I Module (B33); If Voltage < Permitted Value: Check Voltage between measuring sockets 3 & 4 on Amplifier Filter Module (B40) and outdoor equipment. If Voltage >= Permitted value : Replace Receiver –I Module (B33)

13 ○ ○ ● ● ● ● ● ● ● ● ○ ● ○ ● ○ UP DN Replace Receiver - I Module (B33)

14 ○ ○ ● ● ● ● ● ● ● ○ ● ○ ● ○ ● DN UP Replace Receiver - I



16

Sr. No.

Power Unit



Receiver I B33

Demo-dulator B35

Receiver II B39-B34

Relay module B36


12V 5V L1 L2 L3 L8 L9 L4.1 L4 I L5

II L5

I L6

II L6

I L7

II L7

GF1 GF2

Module (B33) 15 ○ ○ ● ● ● ● ● ● ● ● ● ● ○ ● ○ UP DN Replace Demodulator

Module (B35) 16 ○ ○ ● ● ● ● ● ● ● ● ● ○ ● ○ ● DN UP Replace Demodulator

Module (B35) 17 ○ ○ ● ● ● ● ● ● ● ● ● ○ ○ ○ ○ DN DN Replace Demodulator

Module (B35) 18 ○ ○ ● ● ● ○ ● ● ● ● ● ● ● ○ ○ DN DN Replace Transmitter

Module (B30); Scanning pulse is faulty.

19 ○ ○ ● ● ● ● ● ● ● ● ● ● ● ○ ○ DN DN Connect Measuring sockets E1 & E2 on Receiver – I Module (B33): If LEDs I L6 and II L6 on the Demodulator Module (B35) do not switch OFF, Replace Demodulator Module (B35). If LEDs I L6 and II L6 on the Demodulator Module (B35) switch OFF, Replace Receiver

20 ○ ○ ● ● ● ● ● ● ● ● ● ● ● ○ ● DN UP 21 ○ ○ ● ● ● ● ● ● ● ● ● ● ● ● ○ UP DN



17

Sr. No.

Power Unit



Receiver I B33

Demo-dulator B35

Receiver II B39-B34

Relay module B36


12V 5V L1 L2 L3 L8 L9 L4.1 L4 I L5

II L5

I L6

II L6

I L7

II L7

GF1 GF2

Module (B39 for Point zone track circuit or B34 for straight track circuit). Note: Preceeding track circuit in a cascade must be clear.

22 ○ ○ ● ● ● ● ● ● ● ● ● ● ● ● ● DN DN Replace Relay Module (B36)

23 ○ ○ ● ● ● ● ● ● ● ● ● ● ● ● ● DN UP Replace Relay Module (B36)

24 ○ ○ ● ● ● ● ● ● ● ● ● ● ● ● ● UP DN Replace Relay Module (B36)

○ – LED OFF ● – LED ON/Flickering


Section V – Alstom DigiCode AFTC May 2013

1

Section V

vYLVkWe fMft dksM vkWfM;ks fÝDosalh Vªsd lfdZV ALSTOM DIGI CODE


5.1 ifjp; Introduction The Alstom DIGICODE is a remote-fed, joint-less and coded Audio Frequency track circuit. It can feed upto a maximum distance of 3.5 Km. It is designed as a track vacancy detection system for railways (mainline and stations), underground, urban and suburban railways. The system is modular in design and equipped with a diagnostic board indicating the characteristic voltages and currents. In Digi Coded AFTC system the Minimum Shift Keying (MSK) technique is used. A train or vehicle is detected by feeding audio frequency signals with a specific protection codes in the track.

Fig. 5.1: Block Diagram of DIGICODE AFTC 5.2 oxhZdj.k Classification DIGICODE is available in two versions namely DTC 24 and DTC 921. DTC 24 It is used for longer track circuits on main line. It can cater for track circuits length from 100 mtr. to 700 mtr. in case of end-fed configuration and upto 1000 mtr. in case of centre-fed configuration. DTC 24 has following variants:



2

DTC 24 (LF) – End fed. DTC 24 (LF) – Center fed.

DTC 921 It is used for short length track circuits on main line, points and crossings. It can cater track circuits length from 30 mtr. to 400 mtr. DTC 921 has following variants:

DTC 921 (HF) – End fed. DTC 921 (HF) – 2 Receiver (Point zone) DTC 921 (HF) – 3 Receiver (Point zone)

Operating frequencies and code allocation Table I - DTC 24

S. No. Carrier

Frequency name

Frequency (Hz) Allowed Codes

1 F1 2100 C1,C2,C3 2 F2 2500 C4,C5,C6 3 F3 2900 C7,C8,C9 4 F4 3300 C10,C11,C12 5 F5 3700 C13,C14,C15 6 F6 4100 C16,C17,C18

Table II - DTC 921

S. No Carrier

Frequency name

Frequency (Hz) Allowed

codes

1 F7 9500 C19,C20,C21 2 F8 11100 C22,C23,C24 3 F9 12700 C25,C26,C27 4 F10 14300 C28,C29,C30 5 F11 15900 C31,C32,C33 6 F12 17500 C34,C35,C36 7 F13 19100 C37,C38,C39 8 F14 20700 C40,C41,C42

5.3 iz.kkyh dh jpuk System description

5.3.1 Indoor equipment (a) Evaluator

Evaluators are placed in a rack which is either an open rack or a closed cubical.

An open rack contains upto 3 sub-racks. Each sub-rack contains 2 DIGICODE evaluators hence overall each open rack can accommodate upto 6 DIGCODE evaluators. Open rack also contains relay bracket at the top to accommodate track relays. Alternatively, 6 end fed track circuits or 3 center fed track circuits or 6 point zone track circuits can be installed in one open rack.



3

Similarly, a closed cubical rack contains upto 5 sub-racks. Each sub-rack contains 2 DIGICODE evaluators hence overall each rack can accommodate upto 10 DIGCODE evaluators The Evaluator consists of following modules Tx-Rx Module RT Module (Train detection module) Modem board Point Rx board (For point zone track circuits) Diagnostic board (Optional)

Fig. 5.2: DIGICODE Evaluator front view

(b) Power Supply Unit Input 230 V AC + 10% 50 Hz + 2% or 110 V AC + 10% 50 Hz + 2%

Fig.5.3: DIGICODE Evaluator rear view (c)Lightning Discharger Lightning Discharger (LD) is connected in between the AFTC indoor equipment & Field cables. It is provided to safe guard the AFTC equipment from high voltage emerging from Lightning. It is a class D type.

POWER CONV.-1 POWER CONV.-2



4

(d) Constant Voltage Transformer It has been recommended in areas where power fluctuations are more than 10%.It is a Ferro resonant type CVT. One CVT(1000W) can cater for 6 Nos of End Fed or 3 Nos of Center Fed or 6 Nos of Point Zone Track circuit. 5.3.2 Outdoor equipment Tuning units Bonds for separation of two adjacent AFTCs -S-bonds, Alpha-bonds or Shunt bonds

Fig. 5.4: DIGICODE Tuning Unit connections

Tuning Unit connections: CN3 – Always to lower frequency A – Always to lower frequency CN4 – Always to higher frequency B – Always to Centre of bond C – Always to higher frequency 5.4 dscy fcNkus gsrq ;kstuk Cabling scheme Power wiring (indoor) – 6 Sq.mm.Multi-strand wire The connection between the Tuning Unit (TU) and Processing Unit is provided through one pair of 0.9 mm dia quad cable – single conductor upto 1 Km distance and double conductors are used beyond 1 Km. Tuning Unit to rail connection – 25 Sq. mm. Copper cable. Electric joint S-bond, Alpha bond or Shunt bonds - 145 Sq.mm Galvanized Steel cable

5.5 rdfudh vkadMs Technical data Table III

S. No.

Characteristics DTC 24

(Main Line) DTC 921

(Station/ Transit) 1 Maximum TC Length 700m-EF,1000m-CF 400m-EF 2 Minimum TC Length 100m 30m 3 Electric Joint Length 18.6 to 25.4m 6m 4 Ballast Resistance 2 ohm/Km 2 ohm/Km 5 Carrier Frequency Range 2.1KHz-4.1KHz 9.5KHz-20.7KHz 6 No.of Channels 6 8

7 Track Shunt Resistance 0.5 ohm & 0.15 ohm for tuned zone

0.5 ohm & 0.15 ohm for tuned zone



5

8 Power Consumption 50-140 VA(EF),50-200VA(CF)

50-140VA(EF)

9 Input Power 110V±10%, 50 Hz ±2%

110V±10%, 50 Hz ±2%

5.6 fMft dksM ds dkMksZ dh tkudkjh Cards information 5.6.1. For straight track circuits (i)Frequency dependent cards 1. Tx & Rx Module – there are 6 types from F1 to F6 2. Tuning Unit – There are 6 types of TU Boards e.g. F1/F3…..F4/F6. (ii)Universal Cards 1. Mother Board (N897095300Q) – This card can be used for all types of AFTC. 2. RT_NDV Card (N897092015C) - This card can be used for straight track circuits of any

frequency (F1 to F14). 3. Modem Card (Two type) –

I. Modem Card - (N897091012N) - This card can be used for straight track circuits of low frequency (F1 to F6).

II. Modem Card - (N897091013P) - This card can be used for straight track circuits of high frequency (F7 to F14).

5.6.2 For Centre-fed track circuits (i)Frequency dependent cards 1. Tx & Rx Module – there are 6 types from F1 to F6 2. Secondary Receiver (Rx) Module - there are 6 types from F1 to F6 3. Tuning Unit – There are 12 types of TU Boards e.g. F1/F3…..F4/F6 &

F1MPU….F6MPU. (ii)Universal Cards 1. Mother Board (N897095300Q) – This card can be used for all types of AFTC. 2. RT_NDV Card (N897092015C) - This card can be used for straight track circuits of any

frequency (F1 to F14). 3. Modem Card - (N897091012N) - This card can be used for straight track circuits of low

frequency (F1 to F6). 5.6.3 For Point zone track circuits (i)Frequency dependent cards

1. Tx & Rx Module – there are 8 types from F7 to F14 2. Tuning Unit – There are 16 types of TU Boards e.g. F7/F19…..F12/F14.

(ii) Universal Cards 1. Mother Board (N897095300Q) – This card can be used for all types of AFTC. 2. RT_DV Card (N897092012Z) - This card can be used for all types of AFTC (F1 to

F14). 3. Modem Card - (N897091013P) - This card can be used for high frequency AFTCs



6

(iii) Point Receiver Point Rx1 Channel (N897044102PR) – This card can be used for point zone track circuit

with one Transmitter and two Receivers.

Point Rx1 Channel (N897044103PR) – This card can be used for point zone track circuit with one Transmitter and three Receivers

5.7 ,ybZMh ladsr ,oa ijh{k.k fcanq LED indications and testing points

LED indications are provided at the front panel of major modules/cards. For troubleshooting purposes, the voltages at the power unit and measuring sockets of the major modules/cards can be measured. The permitted values are given in tables of Fig. Table IV

Measuring sockets Measuring location

Multi-meter selection

Permitted value Remarks

V-TX@ 50V fuse TX AC (AUTO) 6 – 90 V AC -- V-OUT AT 50V TX AC (AUTO) 2 - 45 V AC -- 50 V DC TX DC (AUTO) 45 – 58 V DC -- 24 V DIG RX DC (AUTO) 22 – 28 V DC -- V-IN RX AC (AUTO) > 0.220 V AC -- V-RX RX AC (AUTO) 0.400 – 1.20 V AC Track Circuit Vacant/Free V-RX RX AC (AUTO) 0.010 - 0.280 V AC Track Circuit Occupied MSR +/- RT DC (AUTO) 9.8 – 25 V DC -- 20 KHZ Voltage RT Hz (AUTO) 24 -32 V AC -- 24 V LOC RT DC (AUTO) 21 – 27 V DC --

VO LT AG E M EAS S U R IN G SO C KET SU SE 2 m m D IA P R O BE O N LY

LED ’s

F U SE

TRIM M ERS

O SC .IN T

O SC .EXT

M O D EM

F2

LF

H F

F1

BIT1 D

BIT0 D

C D

1

2 D EM

4

BIT1 M

BIT0 M

1

2 M O D

4

V.RX

1615

1413

1211

109

87

65

43

21

AD J.VRX

12

34

56

78

910

1112

1314

1516

AD J.VTX

V.TX

V.IN

V.O U T

TX RX

FU SE 2 4 VLO C

2 4 V D IG

FU SE

5 0 V

FU SE

2 0 V LO C

O U T M SR

O U T PU T

2 0 KH z

M SR +

+ 5 V

-1 2 V

+ 1 2 V

G N D

R N

SW 2

SW 1

2 4 V.SW

RT

D ELAY1

M SR -

O SC .IN T

O SC .EXT

M O D EM

F2

LF

H F

F1

BIT1 D

BIT0 D

C D

1

2 D EM

4

BIT1 M

BIT0 M

1

2 M O D

4

O SC .IN T

O SC .EXT

M O D EM

F2

LF

H F

F1

BIT1 D

BIT0 D

C D

1

2 D EM

4

BIT1 M

BIT0 M

1

2 M O D

4

V.RX

1615

1413

1211

109

87

65

43

21

AD J.VRX

12

34

56

78

910

1112

1314

1516

AD J.VTX

V.TX

V.IN

V.O U T

TX RX

FU SE 2 4 VLO C

2 4 V D IG

FU SE

5 0 V

FU SE

V.RX

1615

1413

1211

109

87

65

43

21

AD J.VRX

1615

1413

1211

109

87

65

43

21

AD J.VRX

12

34

56

78

910

1112

1314

1516

AD J.VTX

12

34

56

78

910

1112

1314

1516

AD J.VTX

V.TX

V.IN

V.O U T

TX RX

FU SE 2 4 VLO C

2 4 V D IG

FU SE

5 0 V

FU SE

2 0 V LO C

O U T M SR

O U T PU T

2 0 KH z

M SR +

+ 5 V

-1 2 V

+ 1 2 V

G N D

R N

SW 2

SW 1

2 4 V.SW

RT

D ELAY1

M SR -

2 0 V LO C

O U T M SR

O U T PU T

2 0 KH z

M SR +

+ 5 V

-1 2 V

+ 1 2 V

G N D

R N

SW 2

SW 1

2 4 V.SW

RT

D ELAY1

M SR -

Fig.5.5: LED indications/Test points for Straight Track Circuit (End Fed)

Note: the input power line voltage must be 220/110 Vac ± 5% before the power conversion unit Use only 2 mm dia meter probe. Selection of Mulimeter - TX3 for TEXTRONICS, 187, 189 for FLUKE and 18S IRS for RISHABH



7

Fig.5.6: LED indications/Test points for Straight Track Circuit (Centre Fed)

Table V

OUT MSR RT DC (AUTO) 4.8 – 6.8 V DC Track Circuit Vacant/Free OUT MSR RT DC (AUTO) < 4.2 V DC Track Circuit Occupied OUTPUT RT DC (AUTO) 20 – 28 V DC Track Circuit Vacant/Free OUTPUT RT DC (AUTO) < 0.6 V DC Track Circuit Occupied + 5 V RT DC (AUTO) 4.9 – 5.1 V DC -- - 12 V RT DC (AUTO) -12.2 – 11.8 V DC -- + 12 V RT DC (AUTO) 11.8 – 12.2 V DC --

Measuring sockets

Measuring location



V-TX@ 50V fuse TX AC (AUTO) 6 – 90 V AC -- V-OUT AT 50V TX AC (AUTO) 2 - 45 V AC -- 50 V DC TX DC (AUTO) 45 – 58 V DC -- 24 V DIG RX DC (AUTO) 22 – 28 V DC -- V-IN RX AC (AUTO) > 0.220 V AC -- V-RX RX AC (AUTO) 0.400 – 1.20 V AC Track Circuit Vacant/Free V-RX RX AC (AUTO) 0.010 - 0.280 V AC Track Circuit Occupied MSR +/- RT DC (AUTO) 9.8 – 25 V DC -- 20 KHZ Voltage

RT Hz (AUTO) 24 -32 V AC --

24 V LOC RT DC (AUTO) 21 – 27 V DC -- OUT MSR RT DC (AUTO) 4.8 – 6.8 V DC Track Circuit Vacant/Free OUT MSR RT DC (AUTO) < 4.2 V DC Track Circuit Occupied

VO LTAG E M EASS URING SO CKETSUSE 2m m DIA P RO BE O NLY

LED’s

FU SE

TRIM M ERS

OSC.INT

OSC.EXT

MODEM

F2

LF

HF

F1

BIT1D

BIT0D

CD

1

2 DEM

4

BIT1M

BIT0M

1

2 MOD

4

V.RX

1615

1413

1211

109

87

65

43

21

ADJ.VRX

12

34

56

78

910

1112

1314

1516

ADJ.VTX

V.TX

V.IN

V.OUT

TX RX

FUSE 24VLOC

24V DIG

FUSE

50V

FUSE

20V LOC

OUT MSR

OUT PUT

20KHz

MSR +

+ 5V

-12V

+ 12V

GND

R N

SW2

SW1

24V.SW

RT NDV

DELAY1

MSR -

OSC.INT

OSC.EXT

Sec. MODEM

F2

LF

HF

F1

BIT1D

BIT0D

CD

1

2 DEM

4

BIT1M

BIT0M

1

2 MOD

4

V.RX

1615

1413

1211

109

87

65

43

21

ADJ.VRX

V.IN

Sec. RX

FUSE 24VLOC

24V DIG

FUSE

20V LOC

OUT MSR

OUT PUT

20KHz

MSR +

+ 5V

-12V

+ 12V

GND

R N

SW2

SW1

24V.SW

RT NDV

DELAY1

MSR -

OSC.INT

OSC.EXT

MODEM

F2

LF

HF

F1

BIT1D

BIT0D

CD

1

2 DEM

4

BIT1M

BIT0M

1

2 MOD

4

OSC.INT

OSC.EXT

MODEM

F2

LF

HF

F1

BIT1D

BIT0D

CD

1

2 DEM

4

BIT1M

BIT0M

1

2 MOD

4

V.RX

1615

1413

1211

109

87

65

43

21

ADJ.VRX

12

34

56

78

910

1112

1314

1516

ADJ.VTX

V.TX

V.IN

V.OUT

TX RX

FUSE 24VLOC

24V DIG

FUSE

50V

FUSE

V.RX

1615

1413

1211

109

87

65

43

21

ADJ.VRX

1615

1413

1211

109

87

65

43

21

ADJ.VRX

12

34

56

78

910

1112

1314

1516

ADJ.VTX

12

34

56

78

910

1112

1314

1516

ADJ.VTX

V.TX

V.IN

V.OUT

TX RX

FUSE 24VLOC

24V DIG

FUSE

50V

FUSE

20V LOC

OUT MSR

OUT PUT

20KHz

MSR +

+ 5V

-12V

+ 12V

GND

R N

SW2

SW1

24V.SW

RT NDV

DELAY1

MSR -

OSC.INT

OSC.EXT

Sec. MODEM

F2

LF

HF

F1

BIT1D

BIT0D

CD

1

2 DEM

4

BIT1M

BIT0M

1

2 MOD

4

V.RX

1615

1413

1211

109

87

65

43

21

ADJ.VRX

1615

1413

1211

109

87

65

43

21

ADJ.VRX

V.IN

Sec. RX

FUSE 24VLOC

24V DIG

FUSE

20V LOC

OUT MSR

OUT PUT

20KHz

MSR +

+ 5V

-12V

+ 12V

GND

R N

SW2

SW1

24V.SW

RT NDV

DELAY1

MSR -



8

Selection of Mulimeter - TX3 for TEXTRONICS, 187, 189 for FLUKE and 18S IRS for RISHABH Use only 2 mm dia meter probe

Fig. 5.7: LED indications/Test points for Point Zone Track Circuit

OUTPUT RT DC (AUTO) 20 – 28 V DC Track Circuit Vacant/Free OUTPUT RT DC (AUTO) < 0.6 V DC Track Circuit Occupied + 5 V RT DC (AUTO) 4.9 – 5.1 V DC -- - 12 V RT DC (AUTO) -12.2 – 11.8 V DC -- + 12 V RT DC (AUTO) 11.8 – 12.2 V DC --

Measuring sockets

Measuring location



V-TX@ 50V fuse TX AC (AUTO) 6 – 90 V AC -- V-OUT AT 50V TX AC (AUTO) 2 - 45 V AC -- 50 V DC TX DC (AUTO) 45 – 58 V DC -- 24 V DIG RX DC (AUTO) 22 – 28 V DC -- V-IN RX AC (AUTO) > 0.220 V AC -- V-RX RX AC (AUTO) 0.550 – 1.20 V AC Track Circuit Vacant/FreeV-RX RX AC (AUTO) < 0.280 V CAC Track Circuit Occupied MSR +/- RT DC (AUTO) 9.8 – 25 V DC -- 20 KHZ Voltage

RT Hz (AUTO) 24 - 32 V AC --

24 V LOC RT DC (AUTO) 21 – 27 V DC -- OUT MSR RT DC (AUTO) 4.8 – 6.8 V DC Track Circuit Vacant/FreeOUT MSR RT DC (AUTO) < 4.2 V DC Track Circuit Occupied OUTPUT RT DC (AUTO) 20 – 28 V DC Track Circuit Vacant/FreeOUTPUT RT DC (AUTO) < 0.6 V DC Track Circuit Occupied + 5 V RT DC (AUTO) 4.9 – 5.1 V DC --

VOLTAGE MEASSURING SOCKETSUSE 2mm DIA PROBE ONLY

LED’s

FUSE

TRIM MERS

O SC .IN T

O SC .EXT

M O D EM

F2

LF

H F

F1

BIT1 D

BIT0 D

C D

1

2 D EM

4

BIT1 M

BIT0 M

1

2 M O D

4

PO I N TRX

BIT1 M

BIT0 M

C D

SW 2 O U T

BIT1 D

BIT0 D

C D

SW 1 O U T

V.RX

161 5

141 3

121 1

109

87

65

43

21

AD J.VRX

12

34

56

78

910

1 112

1 314

1 516

AD J.VTX

V.TX

V.IN

V.O U T

TX RX

FU SE 2 4 VLO C

2 4 V D IG

FU SE

5 0 V

FU SE

2 0 V LO C

O U T M SR

O U T PU T

2 0 KH z

M SR +

+ 5 V

-1 2 V

+ 1 2 V

G N D

R N

SW 2

SW 1

2 4 V.SW

RT

D ELAY1

M SR -

O SC .IN T

O SC .EXT

M O D EM

F2

LF

H F

F1

BIT1 D

BIT0 D

C D

1

2 D EM

4

BIT1 M

BIT0 M

1

2 M O D

4

O SC .IN T

O SC .EXT

M O D EM

F2

LF

H F

F1

BIT1 D

BIT0 D

C D

1

2 D EM

4

BIT1 M

BIT0 M

1

2 M O D

4

PO I N TRX

BIT1 M

BIT0 M

C D

SW 2 O U T

BIT1 D

BIT0 D

C D

SW 1 O U T

PO I N TRX

BIT1 M

BIT0 M

C D

SW 2 O U T

BIT1 D

BIT0 D

C D

SW 1 O U T

V.RX

161 5

141 3

121 1

109

87

65

43

21

AD J.VRX

12

34

56

78

910

1 112

1 314

1 516

AD J.VTX

V.TX

V.IN

V.O U T

TX RX

FU SE 2 4 VLO C

2 4 V D IG

FU SE

5 0 V

FU SE

V.RX

161 5

141 3

121 1

109

87

65

43

21

AD J.VRX

161 5

141 3

121 1

109

87

65

43

21

AD J.VRX

12

34

56

78

910

1 112

1 314

1 516

AD J.VTX

12

34

56

78

910

1 112

1 314

1 516

AD J.VTX

V.TX

V.IN

V.O U T

TX RX

FU SE 2 4 VLO C

2 4 V D IG

FU SE

5 0 V

FU SE

2 0 V LO C

O U T M SR

O U T PU T

2 0 KH z

M SR +

+ 5 V

-1 2 V

+ 1 2 V

G N D

R N

SW 2

SW 1

2 4 V.SW

RT

D ELAY1

M SR -

2 0 V LO C

O U T M SR

O U T PU T

2 0 KH z

M SR +

+ 5 V

-1 2 V

+ 1 2 V

G N D

R N

SW 2

SW 1

2 4 V.SW

RT

D ELAY1

M SR -



9

Table VI Selection of Mulimeter - TX3 for TEXTRONICS, 187, 189 for FLUKE and 18S IRS for RISHABH Use only 2 mm dia meter probe

5.8 vuqj{k.k Maintenance

5.8.1 Replacing modules in the rack Before changing any element turn off the power of the rack including the modules to be replaced. It can be easily done either by turning off the front panel switch or the rear Power Conversion switch. A standard screwdriver can be used to unscrew the modules. Before replacing any rack module pay maximum attention to configure the board jumpers following the Putting into Service Manual and the calibration form. In case a TX_RX module is to be replaced, refer to the following instructions: Verify that the new module is of the same channel (frequency) as the original one by

checking the item number of the module; Set the ADJ. V.TX and ADJ V.RX front panel jumpers as the original positions; Verify that V.OUT has a value similar to that reported on the calibration form Verify that V.RX>0.5 Vrms Perform a shunt test on track.

In case a RT board is to be replaced set the P12-P13 and P5-P6 jumpers as the original positions, check the OUTPUT voltage and perform a shunt test on track. In case a MODEM board is to be replaced, set the channel selection (P1, P2, P3 ; P4, P12, P13 and P14) and protection code (P10 and P11) selection jumpers as the original positions. 5.8.2 Power Supply check

The input power line voltage must be 220/110 Vac ± 5% before the power conversion unit. Ie input to the AFTC main cubicle or output of CVT. If no power, check switches (front and rear) in position 1.Ensure that rear Power Conversion fuses are not open, see Fig 5.9 below.

- 12 V RT DC (AUTO) -12.2 – 11.8 V DC -- + 12 V RT DC (AUTO) 11.8 – 12.2 V DC -- SW1 OR SW2 RT AC (AUTO) 4.1 – 4.7 V AC Track Circuit Vacant/FreeSW1 OR SW2 RT AC (AUTO) < 2.50 V AC Track Circuit Occupied SW1 OUT POINT RX DC (AUTO) 5 – 15 V DC -- SW2 OUT POINT RX DC (AUTO) 5 – 15 V DC --



10

POWER CONVERSION1

0

220 V linefuse

10 V

50 V

Fig.5.8: Power Conversion unit fuse

Check of the front equipment fuses. If the front panel power LEDs do not lit, then check whether the corresponding fuse is open. Fuse 50Vcc 4A 250 V Fuse 24V Loc 1A 250 V Fuse 24V Dig 1A 250 V Fuse 12Vcc 1A 250 V (this fuse is inside TX_RX box, symbol F3) If some of the supply voltages is missing despite all the fuses are OK then replace the TX_RX module.

5.8.3 Indoor Adjustments (i) Gain adjustments of voltages in Tx/Rx Cards (Jumpers)

12

34

56

78

910

1112

1314

1516

Minimum

ADJ.VTXMaximum

Maximum

1615

1413

1211

109

87

65

43

21

ADJ.VRX

12

34

56

78

910

1112

1314

1516

Minimum

ADJ.VTXMaximum

Maximum

1615

1413

1211

109

87

65

43

21

ADJ.VRX

Fig. 5.9: Jumper selection for Gain adjustments in Tx/Rx cards

7-8 & 9-10 for minimum Gain setting Minimum 380 mV – 1.3 V Rx Voltage is obtained by regulating the above setting. (ii) Do’s & Don’ts for adjustments in Tx/Rx cards The V-Tx and V-Rx jumpers provided on the Tx-Rx Modules should be correctly positioned as indicated in Fig. below. Do not position the jumpers wrongly. .



11

12

34

56

78

910

1112

1314

1516

12

34

56

78

910

1112

1314

1516

12

34

56

78

910

1112

1314

1516

12

34

56

78

910

1112

1314

1516

12

34

56

78

910

1112

1314

1516

12

34

56

78

910

1112

1314

1516

RIGHT WRONG X

Fig. 5.10: Sketch showing correct and incorrect jumper selection for Gain adjustments in Tx/Rx cards

Don’t swap or remove any card in “Power ON” condition. Power must be OFF through the switch provided on front panel of Tx-Rx cassette. If there is a track circuit failure, please check the outdoor gears first prior to changing any cards of processing equipment. Don’t touch the semiconductors (ICs) of the boards with bare fingers, as they are sensitive to static electricity No adjustments are required to be done in outdoor tuning unit. 5.9 =qfV;ksa ds y{k.k Fault Diagnosis (i) OUTPUT is not present If the V.RX signal is present, (> 0.5 Vrms), but the OUTPUT is not present, then check if DELAY1 LED lits; If DELAY1 LED does not lit, then check the MODEM front panel showing the dynamic operation of the board, i.e. BIT1M and BIT0M LED flashing, CD green LED firmly liting, BIT1D and BIT0D LED flashing. If this is not the case, then replace the MODEM board. If the MODEM works, but DELAY1 does not lit, then comparator or delay1 module have failed; replace the RT board. If DELAY1 LED does lit, but OUT.MSR does not lit, then either the output stage of the RX filter or the 20 kHz generator or the magneto static relay might have failed. Check the MSR+ and MSR- voltage greater then 11 Vdc; if this voltage is not present, then the RX filter output stage has failed. Replace the TX_RX module. Check the 20 kHz test points greater than 24 Vrms; if this is not the case, then replace RT board. If the OUT.MSR LED lits and the relative test points have a voltage from 5.1 to 6.8 Vdc, but the OUTPUT is not present, then the delay2 module has failed. Replace the RT board. (ii) V.RX is not present If track circuit is free this signal must be greater than 0.5 Vrms; Check that V.IN signal has an amplitude greater than 0.6 Vrms



12

If V.IN is not present check the signal on the Cable entry rack by means of the multi-meter, if the RX signal is not present on entry rack, then check if the TX signal is present on the entry rack; if TX is not present, then V.OUT must be verified; if TX on cable entry rack is present, then check if the signal reaches the transmitting tuning box via the cable, then check the receiving tuning box;

If the fault is at outdoors, check Electric Joints and Tuning Unit and try rectifying them.

(iii) V.OUT is not present Check if V.TX signal is present. If it is not present, then replace MODEM board. If the V.TX signal is present and V.OUT is less then the value recorded during commissioning, then the TX filter has failed. Replace TX_RX module. If V.RX voltage is > 0.7 and SW1/SW2 voltages are > 4.5 and there is no out MSR or output, check 20 KHz signal availability on RT card. If 20 KHz signal is not present, then replace POINT RX card.

5.10 VwyfdV Tool Kit

Table VII- Indoor Toolkit Sr. No. Description Size Make Spec./Part No. 1. Digital Multimeter Standard TEXTRONICS or

FLUKE or RISH TX3, 187, 189, 18S

2. Frequency selective voltmeter

385X265X100 ALSTOM 441FSV

3. Screw Driver Set TAPARIA or EASTMAN

Standard

4. Insulated Mini Nose Plier -Round

6” TAPARIA or EASTMAN

Standard

5. Wire stripper & Cutter Standard MULTITECH 150B 6. Non-Metallic Long Screw

Driver (for adjustments) 6 mm dia X 150 mm long

Reputed make Standard

Table VIII- Outdoor Toolkit Sr. No. Description Size Make Spec./Part No.

1. TSR Box -- ALSTOM A489441001A 2. Hydraulic Tool Kit -- ALSTOM 441900100 3. Screw Driver Set TAPARIA or

EASTMAN Standard

4. Screw Driver (Long) 6 mm dia X 250 mm

TAPARIA or EASTMAN

826

5. Nut Driver 7(M4) TEPCO Standard 6. Nut Driver 10(M6) TEPCO Standard 7. Insulated Mini Nose Plier -

Round 6” TAPARIA or

EASTMAN Standard

8. Wire stripper & Cutter Standard MULTITECH 150B 9. Double ended spanner 12 X 13 TAPARIA or

EASTMAN 16/E2001/3

10. Double ended spanner 14 X 15 TAPARIA or EASTMAN

16/E2001/3


16/E2001/3



13


16/E2001/3


16/E2001/3

14. Hammer with long handle 500 gm Standard AS per IS841-83 15. Non-Metallic Long Screw

Driver (for adjustments) 6 mm dia X 150 mm long

Reputed make Standard

Note: A wireless set or mobile phones may be used for communication between field and AFTC center location.



14

5.11 =qfV fuokj.k gsrq ¶ykspkVZ Troubleshooting Troubleshooting Flowchart 1 Troubleshooting Flowchart 2

Is V.OUTon the TX_RX module

close to the value it hadat commissioning

?

Check of Modulatorand TX board

Replace theModem board

Is the signal atjumper P23 similar to

that of fig.5-4?

NO YES

Is V. TXon the TX_RX

module close to the valueit had at

commissioning?

NO YES

YESOK

Replace TX_RX module

Connect a probe to jumperP23 and ground GND4on the Modem board

Replace TX_RX module

TX filter has failed

NO

Locate connectionsof the TX cable insidethe cable entry rack or on the CN2 connector

Fault location

Does theOUTPUT led on

the RT boardlit ?

The problem islocated after thereceiving circuits

YES

Check Mother board,cabinet wiring, trackrelay or Interlocking

NOThe problem islocated either insideDigicode ProcessingUnit or in the track

Is V.OUTon the TX_RX module

close to the value it hadat commissioning

?

YES NO

Go to “Transmittercircuits” Flowchart

The problem is locatedafter the TX board

Is voltageat above mentioned

connections close to thevalue it had atcommissioning

?

NO YESThe fault is located either in the cabinetwiring or on the RXboard (1)

(1) Both TX and RX signals go through the RX board

The fault is located either in the track or inthe receiving circuits

Is V.RXon the TX_RX module

greater than 0.5 VRMS?

YES NOGo to “Receivingcircuits” Flowchart

Are ADJ. V.RXjumpers in the position

they were set atcommissioning

?

YES NOThe problem is locatedeither in the field equipmentor in the track

Re-establish commissioningset-up



15

Troubleshooting Flowchart 3 Troubleshooting Flowchart 4

Istrack voltage

at the TX end of the t.c.close to VAB (VBC)

?

Check of tracksideequipment

Possible failure at the TX pair of the cable

NO YES

Isvoltage at

A-B (B-C) terminals of the TX tuning unit

>0.04xVCN3

(VCN4)?

NO YES

NOVerifify integrity of the S_Bond cable and its rail connections

Replace theTuning Unit board

YES

Isvoltage at

terminals CN3 (CN4)of the TX tuning unit

>3.6xV.OUT?

Istrack voltage

at the RX end of the t.c.>0.12 Vrms

?

YES NO

Broken rail, short circuitbetween the rails or involuntary earth connection

Istrack voltage

at the RX end of the t.c.close to VAB (VBC)

?

NOVerifify integrity of theS_Bond cable and itsrail connections

YES

IsVCN3 (VCN4)

in the RX tuning unit>1.15 Vrms

?

NO YES

Replace theTuning Unit board

Possible failure at the RX pair of the cable

Receiving circuitscheck

IsMSR+,MSR-

on the RT board> 10 Vdc

?

NO YES

DoBIT0D

and BIT1Dlit ?

NOYES

Demodulatorhas failed.Replace MODEMboard

Doesthe Delay 1 led on

the RT boardlit ?

YES

Does theOUTMSR led on

the RT boardlit ?

NO

Either 20 kHz oscillatoror MSR has failed

Delay 2 circuit has failed

YES

Replace RT board

The signal amplifieron thr RX board hasfailed.Replace TX-RX module

Either Comparator orDelay 1 circuit has failed

Replace RT board

Doesthe Delay 1 led on

the RT boardlit ?

NO YES

OKThe output stage ofthe Demodulator circuitmight be damaged.Replace MODEM board

NO

Restore original RT board

16


Fault Diagnosis/LED indicators combinations for straight track circuits Table IX ○ – LED OFF ● – LED ON/Flashing

S No

TX

RX

RT MODEM

RE

LA

Y

CAUSE ACTION REQUIRED

50 V

24 V

DIG

24 V

LO

C

OU

T

MSR

O

UT

-PU

T

+ 5V

- 12V

+ 12

V

R

N

DE

LA

Y 1

BIT

1M

BIT

0M

CD

BIT

1D

BIT

0D

1 ● ● ● ● ● ● ● ● ○ ● ● ● ● ● ● ● UP Section is clear --

2 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ DN Section is occupied --

3 ○ ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ DN Power conversion 10 V & 50 V fuse failure

Replace

4 ○ ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ DN Tx card 50 V fuse failure

Replace

5 ● ○ ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ DN 24 V DIG fuse failure

Replace

6 ● ● ○ ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● DN 24 V LOC fuse failure

Replace

7 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ○ DN VRx Voltage less than 400 mV

Adjust between 500 mV- 1.2 V

8 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ DN VRx Voltage above 1.3 V Adjust between 500 mV- 1.2 V

9 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● DN Output is not present

Check VRx voltage. Should be 0.5 Vrms. If Delay1 lits, then replace RT card.

10 ● ● ● ● ○ ● ● ● ○ ● ● ● ● ● ● ● DN Output is not present

Check VRx voltage. Should be 0.5 Vrms. If Delay1 & OUT MSR lits, then the Delay2 module of RT might have failed. Replace RT card.

11 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● DN DELAY1 does not lit

Check VRx voltage. Should be 0.5 Vrms. Check Modem, if all indications are available then Comparator or Delay1 module of RT might have failed. Replace RT card.

12 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● DN DELAY1 does not lit

Check VRx voltage. Should be 0.5 Vrms. Check Modem, if all indications

17


S No

TX

RX

RT MODEM

RE

LA

Y

CAUSE ACTION REQUIRED 50

V

24 V

DIG

24 V

LO

C

OU

T

MSR

O

UT

-PU

T

+ 5V

- 12V

+ 12

V

R

N

DE

LA

Y 1

BIT

1M

BIT

0M

CD

BIT

1D

BIT

0D

are not available then Output stage of Modem might have failed. Replace MODEM card.

13 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ○ ● DN BIT1D & CD do not lit

Check VRx voltage. Should be 0.5 Vrms. Replace MODEM card

14 ● ● ● ○ ○ ● ● ● ○ ● ● ● ● ● ● ● DN OUT MSR does not lit

If Delay1 lit then check MSR+ . If not available then replace Rx Module.

15 ● ● ● ○ ○ ● ● ● ○ ● ● ● ● ● ● ● DN OUT MSR does not lit

If Delay1 lit then check if 20 kHz is greater than 24 Vrms . If not then replace RT Card.

16 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● DN VRx is not present

Check V IN signal . If V IN is more than 0.2 Vrms then replace Rx module.

17 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ○ ● DN V IN is not present

Check the Receiver signal on CT rack/LD load side. If it is available then replace LD or Rx cable to motherboard.


Check track voltage at the Rx and voltage across AB or BC > 0.12 Vrms of TU VAB or VBC. If not then check for broken rail, short circuit between rails or S or Track lead wire cut.


Check track voltage at the Rx and voltage across AB or BC > 0.12 Vrms of TU VAB or VBC and then check voltage at CN3 or CN4 in the Rx tuning unit >1.15 Vrms of track voltage. If not replace Receiver TU.

20 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ○ DN V Tx is not present

Check the Transmitter signal from Modem on P23 with GND4. If the signal is not present, replace Modem.

21 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ○ DN V OUT is not present

Check VTx signal is present and V OUT is less than the original value, then replace Tx module.

18


○ – LED OFF ● – LED ON/Flashing Fault Diagnosis/LED indicators combinations for Point zone track circuits

Table X

S N

o

Tx Rx RT MODEM POINT RECEIVER

RE

LA

Y

CAUSE ACTION REQUIRED 50

V

24 V

DIG

24 V

LO

C

OU

T M

SR

OU

T-P

UT

+ 5V

- 12V

+ 12

V

R

N

DE

L-A

Y 1

BIT

1M

BIT

0M

CD

BIT

1 D

BIT

0D

CD

BIT

1 D

BIT

0D

1 ● ● ● ● ● ● ● ● ○ ● ● ● ● ● ● ● ● ● ● UP Section is clear - -

2 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ ○ ● ○ DN Section is occupied

--

3 ○ ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ ○ ● ○ DN Power conversion 10 V & 50 V fuse failure

Replace

4 ○ ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ ○ ● ○ DN Tx card 50 V fuse failure

Replace

5 ● ○ ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ ● ● ● DN 24 V DIG fuse failure

Replace

6 ● ● ○ ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● ○ ● ○ DN 24 V LOC fuse failure

Replace

7 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ○ ● ● ● DN VRx Voltage less than 400 mV


8 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ● ○ ○ ● ○ DN VRx Voltage above 1.3 V


9 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● ● ● ● DN Output is not present

Check VRx voltage. Should be 0.5 Vrms. If Delay1 lits, then replace RT card.

19


S N

o


RE

LA

Y


50 V

24 V

DIG

24 V

LO

C

OU

T M

SR

OU

T-P

UT

+ 5V

- 12V

+ 12

V

R

N

DE

L-A

Y 1

BIT

1M

BIT

0M

CD

BIT

1 D

BIT

0D

CD

BIT

1 D

BIT

0D

10 ● ● ● ● ○ ● ● ● ○ ● ● ● ● ● ● ● ● ● ● DN Output is not present

Check VRx voltage. Should be 0.5 Vrms. If Delay1 & OUT MSR lits, then the Delay2 module of RT might have failed. Replace RT card.

11 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● ● ● ● DN DELAY1 does not lit

Check VRx voltage. Should be 0.5 Vrms. Check Modem, if all indications are available then Comparator or Delay1 module of RT might have failed. Replace RT card.

12 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● ● ● ● DN DELAY1 does not lit

Check VRx voltage. Should be 0.5 Vrms. Check Modem, if all indications are not available then Output stage of Modem might have failed. Replace MODEM card.

13 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ○ ● ○ ○ ● DN BIT1D & CD do not lit

Check VRx voltage. Should be 0.5 Vrms. Replace MODEM card

14 ● ● ● ○ ○ ● ● ● ○ ● ● ● ● ● ● ● ● ● ● DN OUT MSR does not lit

If Delay1 lit then check MSR+ . If not available then replace Rx Module.

15 ● ● ● ○ ○ ● ● ● ○ ● ● ● ● ● ● ● ● ● ● DN OUT MSR does not lit

If Delay1 lit then check if 20 kHz is greater than 24 Vrms . If not then replace

20


S N

o


RE

LA

Y


50 V

24 V

DIG

24 V

LO

C

OU

T M

SR

OU

T-P

UT

+ 5V

- 12V

+ 12

V

R

N

DE

L-A

Y 1

BIT

1M

BIT

0M

CD

BIT

1 D

BIT

0D

CD

BIT

1 D

BIT

0D

RT Card. 16 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ● ● ● ● DN

VRx is not present

Check V IN signal . If V IN is more than 0.2 Vrms then replace Rx module.

17 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ○ ○ ● ○ ○ ● DN V IN is not present

Check the Receiver signal on CT rack/LD load ide. If it is available then replace LD or Rx cable to motherboard.


Check track voltage at the Rx and voltage across AB or BC > 0.12 Vrms of TU VAB or VBC. If not then check for broken rail, short circuit between rails or S or Track lead wire cut.


Check track voltage at the Rx and voltage across AB or BC > 0.12 Vrms of TU VAB or VBC and then check voltage at CN3 or CN4 in the Rx tuning unit >1.15 Vrms of track voltage. If not replace Receiver TU.

20 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ○ ○ ● ○ DN V Tx is not present

Check the Transmitter signal from Modem on P23 with GND4. If the signal is not present, replace Modem.

21


S N

o


RE

LA

Y


50 V

24 V

DIG

24 V

LO

C

OU

T M

SR

OU

T-P

UT

+ 5V

- 12V

+ 12

V

R

N

DE

L-A

Y 1

BIT

1M

BIT

0M

CD

BIT

1 D

BIT

0D

CD

BIT

1 D

BIT

0D

21 ● ● ● ○ ○ ● ● ● ○ ● ○ ● ● ● ● ○ ○ ● ○ DN V OUT is not present

Check VTx signal is present and V OUT is less than the original value, then replace Tx module.

22 ● ● ● ○ ○ ● ● ● ○ ● ● ● ● ● ● ● ● ● ● DN SW1/SW2 Voltage less than 4.2 V AC and VRx less than 0.6 V AC

Maintain the switch voltage more than 3.8 V AC and VRx voltage more than 0.6 V AC

23 ● ● ● ○ ○ ● ● ● ○ ● ● ● ● ● ● ● ● ● ● DN SW1/SW2 Voltage more than 3.8 V AC and VRx more than 0.6 V AC, no output present

Check 20 KHz availability and if not present replace Point Rx Card

24 ● ● ● ○ ○ ● ● ● ○ ● ● ● ● ● ● ● ○ ● ○ DN SW1/SW2 Voltage less than 1.9 V AC

Increase the switch voltage by adjusting the DIP switches in Rx Card

○ – LED OFF ● – LED ON/Flashing


Section VI – Ansaldo UM 71 AFTC May 2013

1

Section VI

vulkYMks ;w ,e 71 vkWfM;ks fÝDosalh Vªsd lfdZV ANSALDO UM71

AUDIO FREQUENCY TRACK CIRCUIT 6.1 ifjp; Introduction The UM71 – AFTC is a remote fed, non-coded, joint-less track circuit suitable for all non-RE, RE (DC Traction and AC Traction) areas. In this type of track circuit the Transmitter and Receiver can be centrally provided in the equipment room/relay room maximum 1 Km distance from the track circuit. This track circuit operates on frequency shift principle (FSK) where the basic frequency is shifted between two frequencies close to each other (i.e. basic frequency + 11 Hz) Δ F = 11Hz. Modulation rate is set by division of the basic frequency Fc by 128 i.e. modulation signal frequency =Fc/128.

Carrier Frequency Modulation rate Assigned to V1 - F1 - 1700 Hz 1700/128 = 13.3 Hz Set 1 UP line V1 - F2 - 2300 Hz 2300/128 = 18.00 Hz V2 - F1 - 2000 Hz 2000/128 = 15.6 Hz Set 2 DN line V2 - F2 - 2600 Hz 2600/128 = 20.3 Hz

6.2 iz.kkyh dh jpuk System composition The system consists of following components: Indoor equipment (Equipment at relay room) Field equipment (Wayside equipment) 6.2.1 Indoor equipment The indoor equipment consists of following equipments: (i) Transmitter The transmitter generates a sinusoidal signal, at one of the four basic frequencies (Fc) 1700 Hz; 2000 Hz; 2300 Hz; 2600 Hz.



2

Fig.6.1: Front view of Transmitters of different AFTCs

(ii) Receiver The receiver recognizes the carrier signal in quality (modulated frequency) and in quantity (level).

Fig.6.2: Front view of a Receiver



3

A+ A- 24V DC Input A+ A- 24V DC Input Input from Track on V1 V2 Tx AC Output on V1V8 Fig 6.3.: (a) Nomenclature of connectors in Transmitter (rear view) (b) Nomenclature of connectors in Receiver (rear view)



4

(iii) Relay It is a 24V DC, plug-in-type, non-proved type. (Ordinary Q series line Relay QN1 can be used as a Track Relay). (iv) Power Supply 24 V DC Power supply is required as input to the Transmitter and Receiver which can be taken from a 230 V/24 V Battery Charger with battery backup or through 24 V DC module of an IPS if provided. 6.2.2 Field equipment (Wayside equipment) (i) Tuning & Matching Unit (TMU) There are two types of tuning units: - - Tuning Unit F1 (V1 & V2): This consists of LC (inductive Capacitance) series circuit tuned at a frequency close to F2. - Tuning Unit F2 (V1 or V2): This consists of a LC series circuit, tuned at a frequency close to F1, mounted in parallel with a high value capacitor.

Fig.6.4: TMU at Transmitter end Fig.6.5: TMU at Receiver end (ii) Air Core Inductor (ACI) or O bond On electrified track, a non-saturable inductor, known as the ACI or O bond, is located at the centre of the Electrical Seperation Joint. ESJ length varies from 20 to 29 meters in accordance with Rail type, Sleepers type, Track gauge, Track electrified or non-electrified. There are two types of ACI - The ACI 200 - used for re-equalizing the traction current. - The higher power ACI 600- used for routing the traction return current.

Fig.6.6: Air Core Inductor (ACI) or O bond



5

6.3 dscy fcNkus gsrq ;kstuk Cabling scheme PSU to Tx/Rx - Flexible wire 1 sq.mm. Tx/Rx to TMU - Quad cable - 0.9 mm dia TMU to Rail 70 sq.mm copper or 120 sq. mm Aluminum

6.4 rdfudh vkadMs Technical data Table I At PSU Input voltage 110 V + 25%

Output voltage 24 V DC + 1 At Tx (KEM) Input voltage 24 V DC + 1

Output voltage 25 to 50 V AC Frequency 2300 Hz + 3 Hz Gain adjustment (V1 –V10) V5 toV6 – 3 units

At TMU (Tx end) Input at E1 & E2 25 to 50 V AC Frequency 2300 Hz + 3 Hz Output of TMU 1 to 5 V AC Input across the track 1 to 5 V AC

At TMU (Rx end) Voltage across the track (i.e. input to TMU at Rx end)

0.2 to 0.8 V AC

Output of TMU (Rx end) 0 to 3 V AC i.e. V1 – V2 At Rx (KRV) Input to Rx (V1-V2) 0 to 3 V AC

Voltage at R1 R2 > 250 mV AC Gain adjustment (R3….R10)

KRV 56

At KRV K = Adjustment RV = Rx input

Pick Up T.S.R. 1 Ohm Drop T.S.R. 0.5 Ohm KRV 56

At TR Voltage across TR without T.S.R.

24 to 30 V DC

Voltage across TR with 0.5 Ohm T.S.R.

0 V DC



6

6.5 xsu lasfVax Gain setting For gain setting i.e. increase or decrease of outputs of Tx and Rx the adjustments are to be done as per the following tables 6.5.1 UM71 Gain adjustment table Table II -KEM Table – For Transmitter adjustment KEM (Gain)

Transmitter adjustment Shift Tx Output cable from to

Provide jumpers between

V1 to V8 to 3.00 V4 V7 V5 & V6 V5 & V6 3.25 V1 V7 V2 & V4 V5 & V6 3.50 V2 V7 V3 & V4 V5 & V6 3.75 V1 V7 V3 & V4 4.00 V7 V8 4.25 V1 V8 V2 & V7 4.50 V2 V8 V3 & V7 4.75 V1 V8 V3 & V7 5.00 V4 V8 V5 & V7 5.25 V1 V8 V2 & V4 V5 & V7 5.50 V2 V8 V3 & V4 V5 & V7 5.75 V1 V8 V3 & V4 V5 & V7 6.00 V6 V8 6.25 V1 V8 V2 & V6 6.50 V2 V8 V3 & V6 6.75 V1 V8 V3 & V6 7.00 V4 V8 V5 & V6 7.25 V1 V8 V2 & V4 V5 & V6 7.50 V2 V8 V3 & V4 V5 & V6 7.75 V1 V8 V3 & V4 V5 & V6 Note: By default Tx output is on V1& V8 KTMU & KMU Adjustment tables Table III -KTMU Table IV - KMU

Ratio Connection Cable

Jumpers

Tx Setup

10:1 E1 & E2

Rx Setup

1:1 9 & 10 1:1.5 9 & 12 10 & 11 1:2 8 & 9

Ratio Connection Cable

Jumpers

Rx Setup IDC (*)

1:1 9 & 10 1:1.5 9 & 12 10 & 11 1:2 8 & 9



7

Table V - KRV Table – For Receiver adjustment

KRV Sr. No.

Receiver adjustment Shift connectors from


R1 to R2 to 1 R3 R4 2 R5 R4 3 R3 R5 4 R5 R7 R3 & R6 5 R5 R7 R4 & R6 6 R4 R7 R3 & R6 7 R6 R7 8 R3 R7 R4 & R6 9 R4 R7 R5 & R6 10 R3 R7 R5 & R6 11 R9 R7 R3 & R8 R5 & R6 12 R9 R7 R4 & R8 R5 & R6 13 R9 R7 R3 & R8 R4 & R6 14 R9 R7 R6 & R8 15 R9 R4 R5 & R7 R6 & R8 16 R9 R3 R5 & R7 R6 & R8 17 R9 R3 R5 & R7 18 R9 R5 R3 & R8 19 R9 R5 R4 & R8 20 R9 R4 R3 & R6 21 R9 R8 22 R9 R3 R4 & R8 23 R9 R4 R5 & R8 24 R9 R3 R5 & R8 25 R9 R5 R3 & R6 R7 & R8 26 R9 R5 R4 & R6 R7 & R8 27 R9 R4 R3 & R6 R7 & R8 28 R9 R6 R7 & R8 29 R9 R3 R4 & R6 R7 & R8 30 R9 R4 R5 & R6 R7 & R8 31 R9 R3 R5 & R6 R7 & R8 32 R10 R7 R5 & R6 R3 & R9 33 R10 R7 R5 & R6 R4 & R9 34 R10 R7 R4 & R6 R3 & R9 35 R10 R7 R6 & R9 36 R10 R7 R3 & R6 R4 & R9 37 R10 R7 R4 & R6 R5 & R9

KRV Sr. No.

Receiver adjustment Shift connectors from


R1 to R2 to R3 & R6 R5 & R9 38 R10 R7 R3 & R9 39 R10 R5 R4 & R9 40 R10 R5 R3 & R9 41 R10 R4 42 R10 R9 R4 & R9 43 R10 R3 R5 & R9 44 R10 R4 R5 & R9 45 R10 R3 R3 & R6 46 R10 R5 R3 & R6 R7 & R9 47 R10 R5 R4 & R6 R7 & R9 48 R10 R4 R3 & R6 R7 & R9 49 R10 R6 R7 & R9 50 R10 R3 R4 & R6 R7 & R9 51 R10 R4 R5 & R6 R7 & R9 52 R10 R3 R5 & R6 R7 & R9 53 R10 R7 R5 & R6 R3 & R8 54 R10 R7 R5 & R6 R4 & R8 55 R10 R7 R4 & R6 R3 & R8 56 R10 R7 R6 & R8 57 R10 R7 R3 & R6 R4 & R8 58 R10 R7 R4 & R6 R5 & R6 59 R10 R7 R3 & R6 R5 & R8 60 R10 R5 R3 & R6 61 R10 R5 R4 & R6 62 R10 R4 R3 & R8 63 R10 R8 64 R10 R3 R4 & R6 65 R10 R4 R5 & R8 66 R10 R3 R5 & R8 67 R10 R5 R3 & R6 R7 & R8 68 R10 R5 R4 & R6 R7 & R8 69 R10 R4 R4 & R6 R7 & R8 70 R10 R6 R7 & R8 71 R10 R3 R4 & R6 R7 & R8 72 R10 R4 R5 & R6 R7 & R8 73 R10 R3 R5 & R6 R7 & R8



8

Fig.6.7: Block diagram of a typical UM71 AFTC



9

6.6 vuqj{k.k Maintenance Record readings as per schedule in the following proforma. (With Sample reading) 6.6.1 Indoor Track Circuit No.: A504T Table VI Date Transmitter Reciever Signature

of Maintainer

DC Power Supply

AC Power Supply

DC Power Supply AC Power Supply

A+ A- V1 V8 A+ A- L+ L- V1 V2 R1 R2 07.12.2011 24.46 V 41.20 V 24.36 V 24.46 V 890 mV 348 mV

Fig.6.8: Measurement of AC output voltage in rear of Tx (terminals V1V8)

Fig.6.9: Measurement of AC output voltage at CTB



10

The intactness of wire connectors in rear of Transmitter and Receiver unit should be checked frequently to avoid disconnection. But while doing so it should be ensured that there is no train movement taking place and no signal involving the track circuit under observation is cleared.

Fig. 6.10: Rear view of the Transmitter 6.6.2 Outdoor Table VII - At TMU Tx end Date AC Input at

E1 & E2 Frequency (Hz)

AC Output of TMU

AC Input across the track

Signature of maintainer

07.12.2011 40.5 V 2000 Hz 4.5 V 4.4 V

Fig.6.11: Measurement of AC input voltage at terminals E1 & E2 of Tx end TMU



11

Table VIII -At TMU Rx end

Date AC Voltage across the track (i.e. input to TMU at Rx end)

AC Output of TMU (Rx end)

Signature of maintainer

07.12.2011 0.790 V 0.628 V

Fig.6.12: Measurement of AC output voltage at terminals 9 & 10 of Rx end TMU During every visit (fortnightly) open the TMU apparatus case and check the tightness of outgoing lead wire connected to rail. Tighten it with the spanner provided with the tool kit.

Fig.6.13: Opening of TMU apparatus case



12

Fig.6.14: Tightening of outgoing lead wire

Check the intactness of lead wire connected to rail.

Fig.6.15: Lead wire connection to rail


Section VII – Preventive Maintenance May 2013

1

Section - VII

fuokjd vuqj{k.k PREVENTIVE MAINTENANCE

7.1 vuqj{k.k gsrq tkap Maintenance checks

The following checks shall be performed regularly for preventive maintenance of AFTC:

Visually check the electric joints periodically and ensure that these are in good condition. This includes connection to the rails, condition of electric joint cable, connections to the Tuning Unit, condition of all welded and screw joints on the track (S-bond, terminal bond, shunt bond, connecting ropes, interconnections etc.)

Fig. 7.1: Connections to the rail (a) Connection from Tuning Unit (b) Rail bonds

Check the various voltages indicated in the data sheet of AFTC equipment in consideration to the climatic conditions, and particularly ballast condition. Then compare the values found with the values recorded at the time of putting into operation. In case of significant differences which cannot be justified by different climatic conditions, and in particular if values due to external conditions are found to be in limits, there might be a failure and the cause needs to be investigated. Perform drop shunt test with TSR to adjust the receiver energization level. Ensure that the surfaces of the rails are clean so that a reliable axle shunt can be maintained.

Deterioration of the ballast resistance can be detected by checking receiver voltage periodically.



2

7.2 cká 'kaV }kjk ijh{k.k Testing with external shunt (a) Apply a non-inductive 0.5 Ohm resistance in any position on the track circuit (except for portion of tuned zone/electric separation joints). The respective track relay should de-energize.

Fig. 7.2: Track circuit shunted at any portion except tuned zone.

(b)Check whether a non-inductive resistance of 0.15 Ohm interposed anywhere inside the tuned zone/ESJ causes de-energization of at least one of the two successive track circuits

Fig. 7.3: Track circuit shunted in tuned zone

(c) Apply a non-inductive resistance of 0.15 Ohm in overlap zone of ESJ (Overlap zone as prescribed by manufacturer). Track relay of both the AFTCs should drop

Fig. 7.4: Track circuit shunted at overlap zone of ESJ



3

7.3 vuqj{k.k ds le; lko/kkfu;ka Precautions during maintenance After a change in outdoor installation/interconnection, do all the adjustments as applicable for initial installation.

After change of a module of indoor equipment, ensure adjustments/measurements in the changed module as per initial installation and TSR test should be conducted.

Perform the TSR adjustment in dry weather conditions only. If same is done during monsoon, ensure that there is no water logged in between rails and ballast/mud/dirt is not touching rails. Repeat the TSR check as soon as weather normalizes and correct the settings.

In failure during monsoon, increase gain adjustment till satisfactory operation is attained. Check TSR without fail. After the monsoon season, restore the gain to original setting, else there could be unsafe failure.

In case a TX_RX module is to be replaced, verify that the new module is of the same channel (frequency) as the original one by checking the item number of the module.

If there is a track circuit failure, check the outdoor gears first prior to changing any cards of processing equipment.

To carry out measurements, the necessary measuring equipment and related tools should be as per the prescribed tool kit. After commissioning, no adjustments should be done except during monsoon when the ballast resistance is affected. In case of failure during monsoon, gain adjustment to be increased till satisfactory operation is attained. TSR should be checked without fail. After the monsoon season the gain should be restored to original setting at the time of commissioning, else there could be unsafe failure.


Section VIII – Do’s & Don’ts May 2013

1

Section - VIII

D;k djsa o D;k u djsa DO’s & DON’Ts

8.1 D;k djsa Do’s Check connection to the rails and condition of electric joint cable on each visit. Earth screen of Isolation transformer. Provide separate Surge arrestor on Rx. Use proper size cable prescribed in the installation manual for Rail Bonding in the

tuned area. Carry out Drop Shunt Test at Rx end. Ensure dropping of relay with TSR of 0.5 Ohms outside and TSR of 0.15 Ohms inside

the tuned area. In case of failure during monsoon, gain adjustment to be increased till satisfactory

operation is attained. TSR should be checked without fail. After the monsoon season the gain should be restored to original setting at the time of

commissioning, else there could be unsafe failure.

8.2 D;k u djsa Don’ts Do not use same power supply for feeding more than one Tx or Rx of same

frequency. Do not take measurements when a train is in the vicinity of Track Circuit in RE area. Don’t keep Level crossing inside tuned area. Don’t provide Impedance bond in tuned area. Don’t change output Relay when Rx is working. Don’t provide Axle Counter Tx/Rx coil within 200 m of AFTC. Don’t provide Axle Counter in or within 18 to 20 m of any tuned area/any ETU. Don’t install AFTC where SEJ falls inside tuned area. Do not short circuit TU or disconnect Tx or Rx from tuning unit unless both adjacent

track circuits are switched OFF. Don’t do adjustments after commissioning except during monsoon when the ballast

resistance is affected.


Section IX – FAQs May 2013

1

Section - IX

Ckgq/kk iwaNs tkus okys iz’u Frequently Asked Questions

Q.1 What are the main advantages of Audio Frequency Track Circuits over

conventional AC/DC Track Circuits? Ans. AFTCs are immune to high levels of interference due to traction harmonics present

in AC or DC electrified areas. AFTC can be universally used in AC, DC and Non-RE sections.

Q.2 Why insulation joints are normally not required in AFTC? Ans. The separation between adjacent track circuits is achieved through Electrical joints

formed with the help of rails, bonds and Tuning units. The mutual interference between adjacent track circuits is avoided by using different frequencies.

Q.3 Why insulation joints are required in point zone provided with Audio

Frequency Track circuits? Ans. In points provided with AFTC, the insulated rails are not connected in series unlike

in conventional track circuits. The legs are connected in parallel and detected individually by separate receivers. Hence insulated joints are required to avoid short circuit at the frog. An example is shown in the figure below.

Fig9.1.: AFTC in point zone

Q.4 Why the signal is not directly passed on from feed end to relay end in an

AFTC? Why modulation is required? Ans. Modulation is required to provide greater security and to enable the information to

be passed along the track without being distorted.


Section IX – FAQs May 2013

2

Q.5 Why AC voltage is used in the operation of AFTC? Ans. In AC voltage, Amplitude, Frequency and Phase are available hence modulation and

de-modulation can be achieved. Q.6 Why Audio Frequency range (20 Hz to 20 KHz) is selected? Ans. Audio Frequency range is selected due to following properties

Non-stationary. Random in nature. Generation is easy. Attachment and extraction of information is easy. High level of noise immunity.

Q.7 Why code bits are required? Ans. To avoid interference of other track circuits with same frequency. For security

purpose. Q.8 What is the role of tuning unit in AFTC? Ans. The tuning unit is provided to adjust the RLC value in given frequency band for

resonance so that maximum signal is transmitted along the track. The tuning unit along with rails and bonds form the resonant R-L-C circuit. The Tx and Rx are resonated to the carrier frequency and have maximum power linkage.

Q.9 What will happen if mode of an AFTC is changed from low power to normal

(high) power? Ans. Change in mode as above can make over- energisation of track relay. This can be

hazardous as under shunted condition track relay may pick up. Q.10 Why different type of bonds (Z-bond, S-bond, Alpha- bond) are provided in

AFTC? Ans. Due to imbalance in traction return currents between both the rails, there is a

possibility that Tuning Unit (TU) may burn. To avoid this bonds are provided between two rails.

Also along with rails and tuning unit these bonds form the resonant R-L-C circuit which helps in maximum signal transmission.


Annexure I – Abbreviations May 2013

ANNEXURE I

laf{kIr 'kCnkoyh ABBREVIATIONS ABB Asea Brown Boveri AC Alternating Current ACTM Alternating Current Traction Manual AF Audio Frequency AFTC Audio Frequency Track Circuit Al Aluminum AWS Automatic Warning System BRS British Railway Specification CT Cable Termination CVT Constant Voltage Trasnsformer CWR Continuous Welded Rail DC Direct Current ESJ Electrical Separation Joint ETU End Termination Unit FSK Frequency Shift Keying FSM Frequency Selective Meter FTGS Remote Fed Coded Audio Frequency Track Circuit Siemens GF1 Track Relay 1 in Siemens AFTC GF2 Track Relay 2 in Siemens AFTC Hz Hertz IB Intermediate Block IP Interlocking Plan IPS Integrated Power Supply IRS Indian Railway Specification KV Kilo Volt KHz Kilo Hertz KR Crossing LD Lightning Discharger LED Light Emitting Diode LWR Long Welded Rail M Central Feed In ME MODEM Modulator-Demodulator MSK Minimum Shift Keying NC Normally Closed NO Normally Open OEM Original Equipment Manufacturer OHE Overhead Equipment OP1 Output 1 OP2 Output 2 PCB Printed Circuit Board RB Railway Board



RDSO Research Designs & Standards Organisation RE Railway Electrification RLC Resistance Inductance Capacitance Rx Receiver ST Standard SWG Standard Wire Gauge TC Track Circuit TPR Track Proving Relay TPWS Train Protection & Warning System TSR Train Shunt Resistance TU Tuning Unit TTU Track Tuning Unit Tx Transmitter VA Volt Ampere W Points



CAMTECH/S/PROJ/2013-14/HB-AFTC/2. 0

Annexure II - References May 2013

ANNEXURE II

lanHkZ REFERENCES

IRS specification No. RDSO/SPN/146/2001.

Alstom DIGICODE Audio Frequency Digital Track Circuit maintenance

guidelines. Siemens FTG S Track Circuit - System Description Siemens FTG S Track Circuit – Instructions for use. Siemens FTG S Track Circuit – Adjusting instructions. Maintenance handbook on Audio Frequency Track Circuit (ABB make)

CAMTECH/S/197

Documents

ij vuqj+{k.k iqfLrdk...Coded Audio frequency track circuit 4.1 ifjp; Introduction 1 4.2 oxhZdj.k Classification 2 4.3 rdfudh vkadMs Technical data 2 4.4 iz.kkyh dh jpuk System composition