BO23 Brochure En

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AXLE COUNTER BO23


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1. PRODUCT DESCRIPTION

Figure 1 - BO23 conguraon sample

1.1. GENERAL DESCRIPTION

The axle counter BO23 is used for railway track secon occupancy control; primarily for the vital control of the

secon occupancy. It can also be used in similar applicaons without limited safety requirements. Examples for the

applicaon of the axle counter BO23 are:

Occupancy control of the staon secons within the staon interlocking system

Occupancy control of the open railroad secons within the automac block system

Occupancy control of the open railroad as a single block between staons

Occupancy control of the several secons in wide level crossing area for the purpose of switching-on /

switching-o the level crossing within the level crossing protecon system

Occupancy control of a shunng staon / marshalling yard secons within the automac coach shunng

system etc.

The axle counter BO23 uses its sensors on each end of a given track secon to connuously control and count the

train axles passing in and out of that secon. If the current number of axles on the secon is equal to zero, and no

disturbance, error or fault is detected, the system will send out informaon that the secon is clear. In all other

cases the track secon occupied informaon is sent out.

With the BO23 equipment the track secon occupancy can be controlled on the secon with two counng points

(on the open railroad secon or the staon track secon), on the secon with 3 counng points (switch point

secon), on the dead end secon with one counng point, on the double slip switch point secon (4 counng

points) or on the mulple switch points secon with maximum 8 counng points.


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1.2. PRINCIPLE OF OPERATION

Axle counter BO23 consists of the outdoor equipment on the track and the indoor equipment in the staon or in the

block secon equipment shelter near the railroad as shown on the gure 2.

Figure 2 - Axle counter BO23 basic structure for occupancy control of one secon with 2 counng points

Transmission path is not considered as a part of the axle counter because the exisng railway signalling and

telecommunicaon cables are usually used. There is a 2-wire connecon between indoor and outdoor equipment

(single 2-wire telecommunicaon twisted pair).


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1.3. ADVANTAGES OF AXLE COUNTERS COMPARED TO TRACK CIRCUITS

The basic principle behind the track circuit lies in the connecon of the two rails by

the wheels and axle of locomoves and rolling stock to short out an electrical circuit. This

circuit is monitored by electrical equipment to detect the presence or absence of the trains.

Wikipedia

Figure 3 - Track circuit soluon logic diagram

Track circuit downsides:

Quality of electric signal from transming rail limited by sleepers and ballast insulaon resistance (mustbe as high as possible) leaking the current issue.

This resistance is a liming factor for maximal length of track circuit. Longer secon has less resistance so

the received signal is appropriately damped.

The rest of the voltage on the receiver must be higher than minimal value in order for track circuit to

funcon properly.

Resistance can depend on hydro-meteorological circumstances and condion of top layer (sleepers and

mud). One single roen sleeper sopped in water or one muddy pool can reduce resistance and leak too

much current so the receiver is no longer excited and declares false occupancy.

Funcon of track circuit depends also on the resistance of short-circuit made by axle. Problems can occur

when small number of axles short-circuits (connects) or when resistance of the axle is too high. Poor short-

circuit (cross rail axle connecon) can occur because of rusty lm on the rail, etc. Return current from tracon can inuence track circuit in two ways. First is saturang the transformer if

the secon is long, return current being high and ground not ideal. The other inuence is made by higher

harmonics close to frequency of the main signal which complicate the detecon of signal. This is enlarged

by introducing the thyristor tracon.

Track circuit requires insulated rail joints. (Even though jointless track circuits are available ,in point zones,

high voltage impulse track circuits with joints are found more reliable)

Track circuit requires bonding and more cabling which increases the cost of installaon, maintenance and

error points.

Track circuits face problems when rail head is contaminated, like rust or accumulated leafs.

Track circuits are not reliable in wet condions, so they cannot be used for tunnel train detecon.

Track circuits cannot be reliable on steel structures (like steel sleeper).


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1.4. EMC, TESTING AND CERTIFICATION

Figure 5 - EMC Cercate for Axle Counter BO23- UNUR issued by TV Rheinland InterTrac

Reg. No: AE 60021770 0001, Issued in: 06/2008

Figure 6 - SIL4 Cercate for Axle Counter BO23 Issuedby TV Rheinland InterTrac

Reg. No: ACR/B 09/241, Issued in: 10/2009

Figure 7 - BO23 system EMC tesng Figure 8 - BO23-UNUR EMC tesng

Figure 9 - BO23 diagnoscs Figure 10 - BO23-UNUR temperature tesng


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2. TECHNICAL SPECIFICATION

2.1. OUTDOOR EQUIPMENT RAIL WHEEL SENSOR ZK24-2 AND TRACKSIDE UNIT

VUR

Power supply (VOD1+, VOD1-): 40V DC to 100V DCSensor power supply (U+, U-): 24V DC 5%

Power dissipaon (VUR + ZK24-2): max. 2.5W

Total power dissipaon with

telecommunicaon cable losses: max. 5W

Output current of basic state of

sensor ZK24-2: channel H: 16mA DC 8%

channel L: 16mA DC 8%

Output current of acve state of

sensor ZK24-2: channel H: 10mA DC 8%

channel L: 10mA DC 8%

Side distance of drop-away from raildetecon of sensor ZK24-2: 5 to 15mm on the whole temperature range, for all rail types

Operang temperature range: -40C to +80C

Relave humidity: up to 100%

Water and dust protecon: IP67 for trackside control unit VUR

IP68 for sensor ZK24-2

Vibraon and shocks resistance: tested according to EN 50125-3

Sensor ZK24-2 - vercal axis: vibraons 5 2000Hz, 28g r.m.s., shocks 200g / 6ms

Sensor ZK24-2 - transversal axis: vibraons 5 2000Hz, 14g r.m.s., shocks 100g / 6ms

Sensor ZK24-2 - longitudinal axis: vibraons 5 2000Hz, 5g r.m.s., shocks 36g / 6ms

Electrical connecon: signal screwdriver terminal blocks

rail ground M16 screw, crimp terminal for 35 to 50 mm wire

Minimal rail wheel diameter: 300mm

Wheel ange height: according to UIC 510-2 (table 1)

Wheel ange thickness: according to UIC 510-2 (table 2)

Rail prole: S45S49UIC54UIC60 (other proles on demand)

Dimensions of VUR case (D W H): 200 230 110 mm

Dimensions of VUR case on column

(D W H): 250 250 645 mm

VUR weight without column: 5.32kg

Column weight: 5.9kg

Sensor ZK24-2 weight (without cable): 1.72kg

Weight of the sensor with mounng

bracket and cable: 6.05kgSensor shield weight: 6.78kg (UIC60); 6.3kg (S49)

Table 1 - Wheel ange height (according to UIC 510-2)

Wheel diameter 330mm to 630mm 630mm to 760mm >760mm

Wheel ange heightMin. 32mm Min. 30mm Min. 28mm

Max. 36mm Max. 36mm Max. 36mm


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Table 2 - Wheel ange thickness (according to UIC 510-2)

Wheel diameter 330mm to 840mm >840mm

Wheel ange thicknessMin. 27.5mm Min. 22mm

Max. 33mm Min. 33mm

2.2. INDOOR EQUIPMENT BO23-UNUR

Power supply: 18V to 80V DC

Stabilized counng point power supply: 96V DC 4%, 8W, galvanically isolated

Total power dissipaon (8 counng

points, power supplied): at 24V DC: 66W

at 48V DC: 65W

at 60V DC: 66W

at 80V DC: 72WOperang temperature range: -30C do +70C, up to 100% RH

Axle counng capacity: 999 axles with indicaon (internal counng up to 32767 axles)

Microprocessor module conguraon: 2-out-of-3

Maximal number of counng points: 8 local + 1 remote via remote indoor device (RS232)

Maximal number of track secons: 6 secons

Output signals: relay safety relay contacts

serial interface RS232

Maximal current switching on safety

relay output contacts: 2A DC

Maximal voltage switching on safety

relay output contacts: 150V DC

Maximal current on optocoupler

output transistors: 50mA

Maximal collector-emier voltage

on optocoupler outputs: 75V

Maximal saturaon voltage

on optocoupler outputs: 1V

Reset inputs voltage: reset acvaon: 1480V DC

reset deacvaon:


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3.1.3. CONFIGURATION 3 - OCCUPANCY CONTROL OF 3 INDEPENDENT SECTIONS

Occupancy control of 3 independent secons is performed with one indoor unit BO23-UNUR whose MPU module

runs the operaonal program BO23-3A-3B-2C. First two secons (A and B) can contain up to 3 counng points and

third secon (C) can contain up to 2 counng points. Figure 17 shows the example of 3 independent staon secons.

Figure 17 - Example of 3 independent secons controlled by one indoor unit BO23-UNUR with operaonal program BO23-3A-3B-2C

Each controlled secon can have less counng points than shown on gure 17. Simultaneous train passage is allowed

over any of two or more counng points.

3.1.4. CONFIGURATION 4 - OCCUPANCY CONTROL OF 4 INDEPENDENT SECTIONS WITH 2

COUNTING POINTS EACH

Occupancy control of 4 independent secons is performed with one indoor unit BO23-UNUR whose MPU module

runs the operaonal program BO23-2A-2B-2C-2D. Each of 4 independent secons (A, B, C and D) can have up to2 counng points. Figure 18 shows two examples of the control of 4 independent staon secons with 2 counng

points each.

CP1 CP2

SECTION A

CP3 CP4

SECTION B

CP5 CP6

SECTION C

CP7 CP8

SECTION D

SECTION A

SECTION B

CP7

CP5

CP8

CP6

CP1 CP2

CP3 CP4

SECTION C

SECTION D

Figure 18 - Two examples of 4 independent secons controlled by one indoor unit BO23-UNUR with operaonal programBO23-2A-2B-2C-2D


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Figure 20 - Two examples of two sets of 3 neighbouring secons controlled by one indoor unit BO23-UNUR with operaonal

program BO23-2A2B2C-2D2E2F

3.1.7. CONFIGURATION 7 - OCCUPANCY CONTROL OF 5 NEIGHBORING SECTIONS

If the most distant counng point is sll in range of the indoor equipment (table 3), the occupancy control of5 automac block secons can be performed with one indoor unit BO23-UNUR whose MPU module runs the

operaonal program BO23-2A2B2C2D4E. Some of these 5 secons can be used for the control of staon secons

(e.g. entrance switch point), while the rest of the secons are used for automac block (gure 21).

Figure 21 - Example of 5 neighbouring secons controlled by one indoor unit BO23-UNUR with operaonal program BO23-2A2B2C2D4E (automac block / staon)

3.1.8. CONFIGURATION 8 - OCCUPANCY CONTROL OF 6 NEIGHBORING SECTIONS

If the most distant counng point is sll in range of the indoor equipment (table 3), the occupancy control of

6 automac block secons can be performed with one indoor unit BO23-UNUR whose MPU module runs the

operaonal program BO23-2A2B2C2D2E3F. Some of these 6 secons can be used for the control of staon secons

(e.g. entrance switch point), while the rest of the secons are used for automac block (gure 22).


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Figure 22 - Example of 6 neighbouring secons controlled by one indoor unit BO23-UNUR with operaonal program BO23-2A2B2C2D2E3F (automac block / staon)

3.1.9. CONFIGURATION 9 - OCCUPANCY CONTROL OF 3 INDEPENDENT STATION SECTIONS AND

ONE BLOCK SECTION BETWEEN STATIONS USING SERIAL RS232 LINK

By preseng the operaonal program BO23-3A-2B-2C-2D, one indoor unit BO23-UNUR can control the occupancy

of 3 independent staon secons (secon A with 3, secon B with 2 and secon C with 2 counng points), and

simultaneously one block secon between staons (secon D) with 2 counng points using the serial RS232

connecon with neighbouring staon. Schemac diagram of the occupancy control of block secon between

staons (secon D) is shown on gure 23.

Figure 23 - Control of the block secon between staons using serial connecon RS232 between indoor units BO23-UNURwith operaonal program BO23-3A-2B-2C-2D

The main goal for using the principle of controlling the block secon between staons is to avoid the wire connecon

to the distant counng point when it is out of range of the indoor equipment (in the case of large distance between

staons), or if the wire connecon between staons is simply undesirable (e.g. if there is not enough twisted pairs forthe whole signalling system), so the bre opc cable is preferred. The closer counng point is in this case connected

via 2-wire twisted pair directly to the indoor unit BO23-UNUR (to the terminal of eight counng point, receiving

module UP8) as in previous examples. The indoor unit receives informaon from the distant counng point of the

block secon via RS232 link between the indoor unit BO23-UNUR in the staon and the indoor unit BO23-UNUR

in the neighbouring staon that controls the more distant counng point directly and runs the same operaonal

program BO23-3A-2B-2C-2D. This link is on both indoor units connected to MPU LINK connector on the front plate

of processing module MPU. Communicaon between two indoor units is performed on the safety principle for

closed transmission systems according to EN50159-1.

The length of the block secon between staons is limited only by the telecommunicaon parameters of used

transmission system (ber opc cable with appropriate converters, type of modem for 2-wire connecon etc.); the

secon can be a few dozen of kilometres long.


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3.2. LEVEL CROSSING APPLICATIONS

3.2.1. TWO INDEPENDENT SECTIONS WITH OVERLAPPING OVER THE ROAD

Figure 24 - Train detecon with axle counter BO23 for level crossing on single track open line (basic conguraon) variantwith two overlapping secons

The train presence on the complete level crossing area is controlled using two independent secons (gure 24);secon A between counng point 1 and counng point 2, and secon B between counng point 3 and counng

point 4. Secons A and B are overlapping over the road. Counng points 1 and 4 are located on calculated distances

for switching the level crossing on.

Basic state of the train detecon unit on level crossing (axle counter BO23) is as follows:

Secon A clear, secon B clear (both secons clear).

Condion for switching the level crossing onis any of the following:

Occupancy (release of the Track Clearrelay on the axle counter BO23) of any of the secons (A or B)

during the regular train passage from any direcon, or caused by eventual disturbance/failure

Occupancy (release of the Track Clear relay) of both secons simultaneously caused by disturbance/failure

Some other way of switching-on if provided, independently from axle counter (e.g. manually by switch/

pushbuons), as well as in case of failure detected in the level crossing system.

Condion for switching the level crossing ois any of the following:

Occupancy (release of the Track Clearrelay and picking of the Track Occupiedrelay) of both secons (A

and B) and clearance (release of the Track Occupiedrelay and picking of the Track Clearrelay) of at least

one secon (A or B) regular train passages including shunng

Occupancy (release of the Track Clearrelay and picking of the Track Occupiedrelay) of only one secon (A

or B) and clearance (release of the Track Occupiedrelay and picking of the Track Clear relay) of the same

secon, in case the other secon is clear all the me shunng train movement with change in direcon,without crossing the road

Seng both secons into the basic (clear) state using the reset manual (locally or remotely) or automac


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Some other way of switching-o if provided, independently from axle counter (e.g. manually by switch/

pushbuons, aer the me-out for automac switch-o ).

3.2.2. THREE ADJACENT SECTIONS

Figure 25 - Train detecon with axle counter BO23 for level crossing on single track open line (basic conguraon) variantwith 3 adjacent secons

The train presence on the complete level crossing area is controlled using 3 adjacent secons (gure 25). Counng

points 1 and 4 are located on calculated distances for switching the level crossing on. Secon B that controls the

occupancy of the road area (island secon) is minimally 20m long, i.e. must be longer than the greatest distance

between two neighbouring axles on the railway vehicles.

For the double track open line 3 more secons on the axle counter BO23 (D, E and F) can be used for the other

track, i.e. 4 more counng points. There is sll only one indoor unit BO23-UNUR in the level crossing house; only

the addional modules (cards) are plugged into it according to the applicaon. One indoor unit BO23-UNUR can

control up to 8 counng points, which can be congured on up to 6 secons (see the User Documentaon of BO23).

Basic stateof the train detecon unit on level crossing (axle counter BO23) is as follows:

Secon A clear, secon B clear, secon C clear (all 3 secons clear).

Condion for switching the level crossing onis any of the following:

Occupancy (release of the Track Clearrelay on the axle counter BO23) of secon A or secon C during

the regular train passage from any direcon or caused by eventual disturbance/failure

Occupancy (release of the Track Clearrelay) of secon B or 2 or 3 any of the secons simultaneously

caused by disturbance/failure

Some other way of switching-on if provided, independently from axle counter (e.g. manually by switch/

pushbuons), as well as in case of failure detected in the level crossing system.


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Occupancy (release of the Track Clear relay and picking of the Track Occupied relay) of secon B and

clearance (release of the Track Occupiedrelay and picking of the Track Clearrelay) of secon B regular

train passages including shunng

Occupancy (release of the Track Clearrelay and picking of the Track Occupiedrelay) of secon A only or

secon C only and clearance (release of the Track Occupiedrelay and picking of the Track Clearrelay) of

the same secon, in case the other two secons are clear all the me shunng train movement with

change of direcon, without crossing the road

Seng all 3 secons into the basic (clear) state using the reset manual (locally or remotely) or automac

Some other way of switching-o if provided, independently from axle counter (e.g. manually by switch/push

buons, aer the me-out for automac switch-o ).

3.2.3. TRAIN DETECTION WITH AXLE COUNTER BO23 FOR LEVEL CROSSING WHICH IS

SWITCHED-ON FROM ONE DIRECTION BY THE STATION INTERLOCKING (FROM THE

STATION)

Figure 26 - Train detecon with axle counter BO23 for level crossing which is switched-on from one direcon by the staon

interlocking (from the staon)

Such a conguraon of the axle counter BO23 is used when the level crossing is switched-on automacally for the

train direcon towards the staon and for the train direcon from the staon the level crossing is switched-on by

seng the exit train routes on the staon interlocking. This is usually the case when the level crossing is located

between the entrance signal and associated distant-signal. Secon B that controls the occupancy of the road area

(island secon) is minimally 20m long, i.e. must be longer than the greatest distance between two neighbouring

axles on the railway vehicles.


Secon A clear, secon B clear (both secons clear).


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long, i.e. must be longer than the greatest distance between two neighbouring axles on the railway vehicles.


Secon A clear.

Condion for switching the level crossing on (although the primary funcon of the axle counter is in this case

switching-o) is as follows:

Occupancy (release of the Track Clearrelay) of the secon A caused by disturbance/failure or possible

non-regular train passages from the staon.


Occupancy (release of the Track Clearrelay and picking of the Track Occupied relay) of the secon A and

clearance (release of the Track Occupied relay and picking of the Track Clearrelay) of the secon A

regular train passages including shunng

Seng the secon A into the basic (clear) state using the reset manual (locally or remotely) or automac

Some other way of switching-o if provided, independently from axle counter (e.g. manually by switch/

pushbuons, aer the me-out for automac switch-o ).

3.2.5. TRAIN DETECTION WITH AXLE COUNTER BO23 FOR LEVEL CROSSING ON A SINGLE

TRACK LINE EQUIPPED WITH AUTOMATIC BLOCK

Figure 28 - Train detecon with axle counter BO23 for level crossing on a single track line equipped with automac block

In case the line is equipped with automac block (more than one secon between staons) and dependency

between the level crossing and automac block system should be provided, the switch-on secon between the

switch-on point and the road that has the block signal in direcon towards the level crossing is split on two secons,

and the addional counng point is located behind the block signal. In example on gure 28, block signals are

located in the level crossing area on both sides regarding the road, so the whole level crossing area is divided into

the 5 secons (AE).

This way the level crossing control system can provide the required dependency with automac block system; e.g. if

the signal Block 1 (gure 28.) shows the stop aspect (red), the level crossing will not switch-on immediately aer

occupaon of the secon A, but only aer signal Block 1 changes the aspect to allow the movement or when thesecon B occupies too etc.


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3.3. OCCUPANCY CONTROL IN STATION

Figure 29 - Example of opmal connecon of axle counters BO23 for small staon control

Figure 29 shows an example of a small staon that uses axle counters BO23 for occupancy control of all staon

secons, between entry signals on both sides. Such a staon with 11 secons / 14 counng points can be controlledby 3 indoor units BO23-UNUR placed in the relay room of the staon, designated in dierent colours on gure

29, together with related secons controlled by appropriate unit. Each counng point (wheel sensor ZK24-2 with

trackside unit VUR) is connected to relay room using only one 2-wire twisted pair, no maer if it belongs to only one

secon (terminal counng point) or two neighbouring secons. Further interconnecons of signals from common

counng points are made among indoor units in the relay room.


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BO23 Brochure En