CHAPTER 1 INTRODUCTION

The Metro rolling stock was initially manufactured by a consortium of companies comprising

ROTEM, Mitsubishi Corporation (MC), and Mitsubishi Electric Corporation (MELCO). The

rolling stocks are now being built by Bharat Earth Movers Limited (BEML). The system is

extensible up to 8 coaches.

1.1 INDIAN METROA $590 million contract for over 400 coaches for phase II has been awarded to BOMBARDIER.

While initial trains will be manufactured in Germany and Sweden, the remainder will be built at

Bombardier's Indian factory in Savli, near Vadodara (Gujrat).

1.2 CURRENT ROUTES

LINE 1 (Dilshad Garden to Rithala via Kashmeri Gate)

LINE 2 (HUDA City Centre (Gurgaon) to Jahangirpuri via Rajiv Chowk & Kashmere Gate)

LINE 3 (Noida City Centre to Dwarka Sector 21 via Rajiv Chowk and Yamuna Bank)

LINE 4 (Yamuna Bank to Anand Vihar ISBT)

LINE 5 (Inderlok to Mundka)

LINE 6 (Central Secretariat to Badarpur)

LINE 7 (Airport METRO Express Line)

Fig. 1.1 Metro map

1.3 MAJOR SECTIONSVEHICLE

1. TIMS

2. BRAKES AND PNEUMATICS

3. AIRCON

4. PA/PIS

5. DOORS

CHAPTER 2

VEHICLE

2.1 TRAIN FORMATIONAt present each train-set consists of four cars. Both ends of the train-set are driving trailer car

and middle cars are motor cars. The trailer cars are defined as "DT" car and motor cars are

defined as "M" car.

The train-set can be controlled as a complete unit or as separate units for various maintenance

activities at the depot.

1) 4 car - DT-M-M-DT

2) 6 Car – DT-M-M-T-M-DT

3) 8 Car – DT-M-M-T-M-T-M-DT

Fig 2.1 Train formation

2.1.1 SALIENT FEATURES

1. Broad Gauge

2. 25 KV Supply Voltage System

3. Light Weight Stainless Steel Structure

4. Three phase A.C. Induction Motor

5. Fail safe braking system with regenerative Braking

6. VVVF Control

7. Reinforced conical rubber primary suspension

8. Secondary Air Suspension

DT DTMM

9. Uniform Floor Height

10. Jerk Controlled Braking

11. Slip/Slide protection

12. Train Integrated Management System

13. PLC based saloon Air-conditioning system

14. Electrically Operated and electronically controlled Saloon Doors

15. Emergency Door

16. ATP/ATO

2.2 SALOON INTERIORThe Interior Facilities consist of the following major components:

Passenger Saloon Light:

The lighting system of the passenger compartment is supplied with AC, DC power and runs the

full length of saloon ceiling with two rows of fluorescent tubes. All AC supply lights are normal

lights and all DC supply lights are emergency lights. The emergency lights are mounted on the

ceiling near each passenger door, as sections in those rows. Gangway Light:

A small circle type of fluorescent light is provided the ceiling of gangway area.

Flooring:

The flooring is composed of the sub-floor of cement composition (UNITEX) and floor covering

of synthetic rubber material.

Insulation:

The inside of roof, side, floor, front and end structure is provided with thermal and noise

insulation. The insulation is of Glass Wool.

Passenger Seating:

All passenger seats are of longitudinal type of seats for 7 persons, 4 persons and 2 persons. Total

numbers of seat are 8 sets per each DT-car and 10sets per each M-car. All seats are mounted on

the side wall.

2.3 GANGWAY

A gangway is the flexible element that allows the movement of people between coupled

vehicles.

2.4 BOGIE

The bogie comes in many shapes and sizes but it is in its most developed form as the motor

bogie of an electric or diesel locomotive.  Here it has to carry the motors, brakes and suspension

systems all within a tight envelope.  It is subjected to severe stresses and shocks and may have to

run at over 300 km/h in a high speed application. 

Bogie Function:

1. To maintain the load of vehicle body

2. To transfer the traction force and braking force

3. To maintain good ride quality and stability

4. To pass the curved track smoothly.

Overall Description of DMRC Bogie:

The bogies, manufactured by Rotem have been developed from an existing proven range. The

bogies are of conventional H frame design, with air suspension located between the body-bogie

interface assembly and bogie frame. The bogies are designed with primary and secondary

suspension systems and centre pivot device. The primary suspension comprises conical rubber

springs between the bogie frame and the bogie interface. Centre pivot device transfers traction

forced between the bogies and the vehicle body by means of mono link system.

Bogie Frame:

The bogie frame is H fabricated frame construction with two side frames and transom. The side

frame provides the mounting for the brake equipment, driving gear mounting brackets, traction

motor mounting brackets, the mono link mounting brackets. The centre part of the side frame

provides the mounting support for the air spring assemblies and the brackets for the brake

equipment.

Fig. 2.2 View of motor bogie frame (Bottom view)

Wheel Set:

The wheel sets are designed to sustain a high axle load into line with the passenger load of one

per seat and standing as 10 persons per meter square. The axle for motor and trailer bogies are

similar, however the power bogie axles are designed to with stand the extra loads imposed by

the traction loads and have additional mounting seats for the driving gear.

Mono linkmounting brackets

Traction motor mounting brackets

Driving gearmounting brackets

Brake equipmentmounting brackets

Wheel Base:

The distance between axle center lines, 2.4 m, is optimized to obtain a bogie with a relatively low

wheel wear rate, whilst maintaining stability throughout its operating speed range. It also achieves

a good distribution of vehicle weight onto the role.

Fig.2.3 Motor bogie wheel set

Fig.2.4 Trailer bogie wheel set

2.5 COUPLERSWe generally couple the bogies according to the need. For instance a DT car and M car make a

single unit. They are not uncoupled frequently; hence the coupling should be permanent.

Accordingly DT-DT coupling is automatic whereas DT-M car coupling is semi permanent.

FAC SPC IAC SPC FAC

Fig.2.5 Couplers

FAC Front Automatic Coupling

SPC Semi permanent Coupling

IAC Intermediate Automatic Coupling

Automatic Coupling:

The coupler enables automatic coupling of railway vehicles. Coupling of two units is achieved

without manual assistance by driving one unit up to a second unit. Automatic coupling is

possible under angular misalignment both horizontally and vertically. The coupler permits the

coupled trains to negotiate vertical and horizontal curves and allows rotational movements.

Besides the mechanical coupling, electric and pneumatic coupling is achieved. The shock

absorbers ensure cushioning effect. Connection of the air pipes is automatically accomplished as

the couplers are mechanically coupled. Uncoupling is achieved automatically by remote control

from the driver’s cab or manually from trackside.

DT DTMM

Semi Permanent Coupling:

The semi-permanent coupler is designed to ensure a permanent connection of railway vehicles

which in traffic form a unit and therefore need not to be separated unless in an emergency or in

workshop for maintenance. The couplers halves are connected by means of easily detachable

muff couplings thus ensuring a rigid, slack free and safe connection. The coupler permits

coupled trains to negotiate vertical and horizontal curves and allows rotational movements.

Connection of the air pipes is automatically accomplished as the couplers are mechanically

coupled. Separation of the coupler halves can only be effected manually.

2.6 TRACTION MOTOR

Fig. 2.6 Types of traction motors

The Traction Motor is a 220 kW, 4 pole, squirrel-cage, 3-phase self-ventilated induction motor.

The Traction Motor employs a Class 200 insulation system. The Traction Motor exterior is a

frame-less type with linking iron core clamps and a coupling plate. The motor frame is equipped

with a vehicle fitting nose and fitting seat.

A fan is mounted to the rotor shaft to draw air into the motor to provide cooling air to the rotor

and stator. The air enters the motor through the air inlet on the top of the non-drive end of the

motor and exits through the vents in the motor frame at the drive end of the motor. A Roller

bearing is used on the drive side of the rotor and Ball bearing is used on the non-drive side of the

rotor.

Location:

Two 220kW Traction Motors are mounted on the transom of each motor car bogie

Function:

The Traction Motor provides the necessary torque to move the train. This torque is applied to

each wheel set in the motor cars via an axle-mounted gearbox, which is connected to the motor

via a coupling. The Traction Motor has the capacity to reduce the speed of the train by acting as

a generator. The momentum of the train causes the motor to rotate, and by adjusting the slip

frequency in the stator, the motor generates power back into the overhead supply. This causes a

braking effect on the train, which reduces the wear rate of the pneumatic brakes.

System controls:

Each motor car has four traction motors (two per bogie), with all four Traction Motors controlled

by a Variable Voltage Variable Frequency controller (VVVF).

Chapter 3

Train Integrated Management System

3.1 INTRODUCTIONTrain Integrated Management System (TIMS) provides a centralized function to monitor the

train borne systems and devices. It also provides the operators interface via a Video Display Unit

mounted on the operator desk. This display unit shows relevant information to the operator

about the status of On board equipment as well as commanded functions.

The Train Information Management System interfaces with the following systems located

throughout the train, these systems are:

Traction Inverter (CI)

Auxiliary Power Supply (SIV)

Brake Electronic Control Unit (Brake System)

Door Control Units

Air conditioners

AVAS & PA

Train Radio

ATC System

The Train Integrated Management System also monitors Train Line status, switch and circuit

breaker positions.

3.2 FAULT DETECTION LEVELS

Fault detection is classified into five critically levels-

Level 1: Critical Fault

Faults that require the immediate action/attention of the train operator are classified as critical

fault.

Level 2: Operating Event

An event which is triggered by the train operator.

Level 3: Maintenance Event

An event that requires the attention of maintenance staff, after the train has completed the

scheduled service operation.

Level 4: Record

A maintenance record that requires the attention of the maintenance staff during scheduled

routine maintenance

Level 5: Notice

Information or reminder to aid the train operator during normal service under defined conditions.

3.3 Tims operation mode

Operator Mode Functions:

The TIMS system has the following functions which are accessible to the driver.

System Check Screens - On this screen, TIMS will display on the main window a list of

Train faults that have been detected.

Fig 3.1 Departure check

Additional information about other systems can be checked by driver by touching the soft keys at

the bottom of the screen display. The available soft keys and corresponding train systems are:

DOOR The status of Door system is displayed.

BRAKES The status of the Pneumatic Brake system is displayed.

POWER The status of the High Tension circuit and equipment is

displayed.

AUX The status of the Auxiliary Power Supply System is displayed.

AIR CON The status of the Air Conditioning system is displayed.

HISTORY A list of previously record critical faults are displayed.

DEPARTURE The departure check screen is displayed.

MAIN The LOGOFF screen is displayed.

Maintenance Mode Functions:

The TIMS system functions available to the operator are also accessible to Maintenance staff. In

addition maintenance staff can also access the following functions.

Data download / upload by TIMS Maintenance Terminal

Data and status check on VDU

Fig 3.2 Maintenance menu

3.4 AUXILIARY POWER SUPPLY SYSTEM

The Auxiliary power supply System is divided into two sub-systems:

1. STATIC INVERTER

2. BATTERY

3.4.1 STATIC INVERETER

Location:

Auxiliary Converter Box (SIV Box) is located on the under frame of each DT car.

Function:

The function of SIV is to provide stable power supply to the train auxiliary loads of one unit

(DT+ M).

Main Parts of SIV:

Input charging contactor IVK 1&2 (for making contact between input converter unit)

Output contactor SIVK (for connectivity between output of inverter and load)

Relay unit (It contains different relays such as VCBTPR, SDRXR, SIVFLR and SIVKAR)

Power unit (It contains IGBT’s)

Charging resistor (RC) unit (Prevents high inrush current during initial charging)

Transducers (For monitoring of different parameters)

Input filter reactor (For reducing harmonics towards OHE)

Input filter capacitor (For reducing harmonics towards OHE)

Output filter capacitor (For reducing harmonics towards output)

Output filter reactor (For reducing harmonics towards output)

3.4.2 BATTERY

The battery is used for following applications-

1. During Train Start up

a) Aux Compressor

b) Control Circuit Supply

c) Emergency Saloon Lights

2. Emergency loads(when SIV not working)

a) Emergency Saloon Lights

b) Emergency Ventilation

c) Control Circuit Supply

CHAPTER 4 BRAKES AND PNEUMATICS

This section describes the on-board, compressed air auxiliary services required by trains and how

they are provided on the locomotive and passenger vehicles. 

Pneumatic Parts Providing Company:

Knorr- Bremse, Munich, Germany

4.1 Characteristics of Compressed Air

Its astonishing that pneumatics could spread so forcibly and rapidly in such a relatively short

span of time. Amongst among other reason, this is due to the fact that in some problems of

automation no other medium can be used more readily and more economically.

The characteristics that so distinguish compressed air are:-

Amount: Air is available practically everywhere for compression, in unlimited quantities.

Transport: Air can be easily transported in pipelines, even over larges distances. It is not

necessary to return the compressed air.

Storable: A compressor need not be in continuous operation. Compressed air can be stored

in and removed from a reservoir.

Temperature: Compressed air is insensitive to temperature fluctuations. This ensures

reliable operation, even under extreme conditions of temperature.

Explosion Proof: Compressed air offers no risk of explosion or fire, hence no expensive

protection against explosion is required.

Cleanness: Compressed air is clean since any air which escapes through leaking pipes or

elements does not cause contamination.

Construction: The operating components are of simple construction, and are therefore

inexpensive.

Speed: Compressed air is very fast working medium. This enables high working speed to be

attained. (Pneumatic cylinders have a working speed of 1-2 m/sec.)

Adjustable: With compressed air components, speed and air are infinitely variable

Overload Safe: Pneumatic tools are operating components, can be loaded to the point of

stopping and they are therefore overloading safe.

In order to be able to accurately define the areas of application of pneumatics, it is also

necessary to be acquainted with negative characteristics:-

Preparation: The compressed air needs good preparation. Dirt and humidity should not be

present. (They cause wear of pneumatic components.)

Compressible: It is not possible to achieve uniform and constant piston speed with

compressed air.

Force Requirement: Compressed air is economical only upto a certain force requirement.

Under the normally prevailing working pressure of 700 KPa (7 bar) and dependent on the

travel and speed, the limit is between 20000 and30000 N.

Exhaust Air: The exhaust air is loud. This problem has now, however been resolved due to

the development of sound absorption material.

Costs: Compressed air is a relatively expensive means of conveying power. The high energy

costs are partially compressed by inexpensive components and higher performance (number

of cycles.

4.2 Safety Features

If main air compressor is malfunctioning, information is shown to train operator

through HMI (Human Machine Interface) i.e. TIMS.

Air dryer’s malfunctioning is also shown on TIMS.

In case of, emergency brake applied due to opening of emergency loop, and then also

information is provided on TIMS (Train Integrated Management System).

If any of the components of BCU is malfunctioning, then also fault is generated on

TIMS.

Also all the indication regarding parking brake and service brakes are provided on TIMS.

Safety valves are provided so that pressure can not be built above specified unit.

Back up brake is provided in case of total failure of electric or electronic equipments.

Signal protection valve is provided (two number in each car) which will stop the air

supply to other car in case of heavy leakage in other car.

Air supply is used into the following components-

1. Air Suspension

2. Air Brakes

a. Service brakes

b. Emergency brakes

c. Holding brakes

d. Parking brakes

e. Backup brakes

3. Air horns

4. Pantograph

4.3 AIR SUSPENSION

Placing the car body on air pressure springs instead of the traditional steel springs has become

common over the last 20 years for passenger vehicles.  The air spring gives a better ride and the

pressure can be adjusted automatically to compensate for additions or reductions in passenger

loads.  The changes in air pressure are used to give the brake and acceleration equipment the data

needed to allow a constant rate according to the load on the vehicle.

In DMRC trains, suspension provided in coaches is of primary and secondary types:-

Primary Suspension: It is of conical rubber spring type. The springs are attached to

spring seat of the bogie frame. The wheelset transfers the forces directly through the

conical rubber springs to the bogie frame. Each of three bogies is fitted with same

springs. The assemblies are interchangeable. The conical bonded rubber springs, which

are mounted above the axle boxes, are used as primary suspension system.

Secondary Suspension: They are provided by air bags which are controlled

pneumatically.

Secondary type is used with two principles:-

1. To ensure good ride quality.

2. To ensure the vehicle floor height remain equal in all riding conditions.

Air bags are provided four in number on each car. They are filled with air, with the help of

leveling valve. Leveling valve will take care of the vehicle floor height in all conditions. These

air bags absorb the shocks giving very good ride comfort.

4.4 AUXILIARY FUNCTION - Pantograph

It is a mechanism which is used to tap electricity from overhead wires. It is a simple mechanism

in which lever moves up and touch the overhead wires to tap or to connect with the electricity.

The movement of this pantograph is controlled pneumatically. For this air is being taken from

main reservoir line and stored in 25l tank. From 25 l tank this air goes to pantograph controlling

unit. This pantograph control unit will use this air to regulate the pantograph mechanism. In case

of no main reservoir supply, additional mini air compressor is provided which will provide air

supply for panto mechanism by using 110 V d.c. supply (it works only for two to three minutes.)

completely dead locomotive is only possible if there is battery power and some compressed air

available to get the pantograph up to the overhead power supply.  After all, nothing will work on

the loco without power.  So, a small, battery powered compressor is provided to give sufficient

compressed air to raise the pantograph.

As soon as the pan is up, full power is available to operate the main compressor. For safety a 9

bar safety valve is also provided to control this mini air compressor. To control this mini air

compressor, a governor is also provided.

Fig. 4.1 Pantograph

4.5 AIR BRAKES

A moving train contains energy, known as kinetic energy, which needs to be removed from the

train in order to cause it to stop.  The simplest way of doing this is to convert the energy into

heat.  The conversion is usually done by applying a contact material to the rotating wheels or to

discs attached to the axles.  The material creates friction and converts the kinetic energy into

heat.  The wheels slow down and eventually the train stops.  The material used for braking is

normally in the form of a block or pad.

The vast majority of the world's trains are equipped with braking systems which use compressed

air as the force to push blocks on to wheels or pads on to discs.  These systems are known as "air

brakes" or "pneumatic brakes".

4.5.1 Types of Brakes

1. Service Brakes:

This is the main braking system which provides braking to train in normal conditions. This

service brakes are provided with electric regenerative pneumatic brakes. A regenerative brake is

a mechanism that reduces vehicle speed by converting some of its kinetic energy into a storable

form of energy instead of dissipating it as heat as with a conventional brake. The captured energy

is stored for future use or fed back into a power system for use by other vehicles. As the driver

applies the brakes through a conventional pedal, the electric motors reverse direction. The torque

created by this reversal counteracts the forward momentum and eventually stops the car.

But regenerative braking does more than simply stop the car. Electric motors and electric

generators (such as a car's alternator) are essentially two sides of the same technology. Both use

magnetic fields and coiled wires, but in different configurations. Regenerative braking systems

take advantage of this duality. Whenever the electric motor begins to reverse direction, it

becomes an electric generator. This generated electricity is fed into a chemical storage battery

and used later to power the train. But it is generally not sufficient to stop the train; therefore

pneumatic auxiliaries are used to further stop the car.

To provide service brakes components involved are:-

a. BECU- Brake Electronic Control Unit:

It is the heart of controlling services and emergency brakes. It gets input on the basis of load

(from air suspension). It has software loaded in it. It also get input from the train operator that

how much braking is required. When train operator demands for braking, he gives signal to

BECU. Accordingly BECU gives command for braking first by electric regenerative braking and

if braking effort is not sufficient then it will give command for pneumatic braking. The braking

provided is load corrected, that is, more the load more will be the pressure applied and less the

load less will be the pressure applied and jerk corrected. During braking, wheel slide protection

is also provided by a pneumatic valve known as anti skid valve. This anti skid valve is controlled

by BECU.

b. BCU-Brake Control Unit:

It takes command from BECU and act accordingly by using valves provided in it. For pneumatic

braking BECU will give electric signal to BCU. These electric signals are converted to

pneumatic signals by BCU. According to these pneumatic signals, BCU will generate pressure

for braking. This pressure is applied to TBU.

2. Emergency Brakes:

It is used in case of emergency conditions. It can be applied by the train operator or in case if

certain conditions are not fulfilled (loop of conditions is broken). This signal will go to BECU

and BECU again give electric signal to BCU and BCU further change this signal into pneumatic

signal and applies emergency brakes. Emergency brake is also load corrected.

3. Parking Brakes:

Four number of parking brake mechanism are provided on each car, two per bogie. Parking

brakes are used for parking the train in depot and these are installed at driving trailer cars (one

set per axle).

Parking brakes can be applied manually or these may apply automatically when the main

reservoir pipe pressure is low.

4. Holding Brakes:

It is provided to prevent the train from rolling back on a rising gradient or from train from

moving at the station. It is also provided by BECU which further command to BCU by applying

holding brake. Holding brakes are seventy percent of full service brakes.

5. Back Up Brake (Bp):

Additional brake pipe controlled, back up brake system is provided in order to take over the

brake control function in case of failure of individual electronic or electrical control elements.

The driver can continue to control the pneumatic friction brake by using the driver’s brake valve.

The driver is able to apply or release the pneumatic brake by operating the driver’s brake valve

installed at the driver’s cab.

CHAPTER 5

AIRCONDITIONING5.1 IntroductionPurpose:

To ensure pleasant temperature and humidity inside the cab and passenger saloon.

A/C Unit Providing Company:

1. Air International Transit (AIT), Australia

2. Sidwal, India

3. AIT+ Sidwal (Joint collaboration)

Fig 5.1 A/C Unit: Top View

Functions:

To achieve and maintain acceptable indoor climate in cab and saloon

To produce quality air for driver and passengers

To protect passengers and driver from the smoke outside the train

To secure CO2 levels inside the train at the time of power failure

Location of A/C Unit on Train:

Two A/C units are mounted on the roof of ends of each car

One cab A/C unit is mounted on the roof behind the cab

5.2 BASIC THEORY

There are two laws that are significant to understand the basic refrigeration cycle and air

conditioning. Thermodynamics’ first law: explains that energy cannot be neither created nor

destroyed, but can be changed from one form to another. Thermodynamics’ second law: The

law state that heat always flows from a material at a high temperature to a material at a low

temperature.

For heat to transfer there has to be a temperature and pressure difference. In the refrigeration

process there are two sections which produce a pressure difference: a high-pressure, high

temperature section (condenser) and a low-pressure, low temperature section (evaporator). The

refrigeration system removes heat from an area that is low-pressure, low temperature

(evaporator) into an area of high-pressure, high temperature (condenser). For example, if cold

refrigerant (40°F) flows through the evaporator and the air surrounding evaporator is 75°F, the

cold 40°F will absorb the heat from the 75°F space: By absorbing the heat from the warm space,

it also cools the space. It then transfers that heat to condenser (high side) through compressor.

A hot refrigerant from the compressor flows to a cooler location the condenser medium (air

surround condenser) for example, the refrigerant will give up the hot vapor heat it absorbs from

the indoor evaporator and becomes cool again and turns back to liquid. To move heat from the

evaporator to the condenser we need refrigerant, and other mechanical components, therefore we

need to understand how heat transfers.

5.3 Refrigerant:

Refrigerant is a chemical substance that air conditioner units use; these refrigerants absorb heat

from low-pressure, low temperature evaporator and condensing at a higher pressure, high

temperature condenser. These refrigerant used be R-22 i.e. C2Cl2F4 Refrigerant can change state

from vapor (by absorbing heat) to liquid (by condensing that heat).

5.4 WORKING AND COMPONENTS

In the basic refrigeration system or any air conditioner system we will have five basic

mechanical components: a compressor, a condenser, a thermal expansion device (metering

device), an evaporator and a refrigeration copper tube that connects them. Evaporator and

condenser act as heat exchangers in the air conditioning system. There are two pressure lines and

two heat exchangers. The low-pressure line is an evaporator (it absorbs heat) and the high

pressure line is the condenser (it rejects heat). The first heat exchange that occurs in this basic

refrigeration cycle is the evaporator.

Evaporator: is a heat exchanger that is responsible for absorbing heat from whatever place

(medium) that needs to be cooled. According to thermodynamics’ second law heat always flows

from a material at a high temperature to a material at a low temperature. Since the evaporator is

at a low temperature than the air surrounding it, it will absorb the surrounding heat until the

refrigerant liquid inside the evaporator coils starts boiling as result of absorb that heat.

Fig 5.2 Working of refrigerator

The liquid refrigerant is vaporized in evaporator coils at a controlled rate and temperature . The

low pressure and low temperature refrigerant in the evaporator coil absorbs heat from the sucked

across the coil by the supply air fan. The air which is a mixture of return air and fresh air passes

through the evaporator coils and is cooled and dehumidified is sent into car saloon evenly.

There will be relatively warm air flowing over the evaporator coil, lets say about 80 degrees. The

air condition system is designed so that the refrigerant will evaporate in the evaporator at a

temperature of about 40 degrees, so that it will be cold compared to the warm air flowing over it.

The system is designed so that the heat in the warm air flowing over the evaporator will be

absorbed by the cold evaporating refrigerant. This cools the air flowing over the evaporator, and

is the reason cold air blows out of your air conditioner.

Compressor: Located between suction line (low side pressure and back pressure) and

discharge pressure (high side pressure, head pressure). The suction line is the line that pulls the

low-pressure and temperature from the evaporator and the discharge line is the line that

compresses and pushes that superheat vapor to the condenser. Its creates a pressure difference in

the air conditioning system by pulling in low-pressure, low temperature vapor from the

evaporator suction line and increasing it to high-pressure, high temperature superheat. This

pressure difference what makes the refrigerate flow in a refrigeration cycle. The compressor is

also known as the heart of the refrigeration system. The compressor is known as the vapor pump.

The refrigerating output is produced by four scroll compressors in each unit. The scroll

compressor is powered directly by 3 phase auxiliary supply. Refrigerating vapor returning from

the evaporator at low pressure enters the compressor and the compressor compresses it. The

refrigerant exists in the compressor at high pressure, high temperature superheated gas via the

compressor discharge valve and flows to the condenser coils.

The compressor is the heart of the system; it keeps the refrigerant flowing through the system at

specific rates of flow, and at specific pressures. It takes refrigerant vapor in from the low

pressure side of the circuit, and discharges it at a much higher pressure into the high side of the

circuit. The rate of flow through the system will depend on the size of the unit, and the operating

pressures will depend on the refrigerant being used and the desired evaporator temperature.

Fig 5.3 Compressor

Condenser: It's a heat exchange; it rejects both sensible (measurable) and latent (hidden) heat

absorbed by the indoor evaporator plus heat of compression from the compressor. There are

three important states that take place in the condenser heat rejection. The first state is it de-

superheat or simply rejects hot superheat vapor (it removes sensible heat). At points 3 and 4 this

the state where it rejects so many saturated vapors heat, it starts changing phase from vapor to

liquid; as the refrigerant reaches point 4 it is 100 percent saturated liquid refrigerant. From points

4 and 5 it removes sensible heat from the saturated liquid refrigerant. This is where we can use a

thermometer and tell how much heat it has removed, as more heat is removed it’s now in the sub

cooled region.. Condenser fan coil is made up of inner screw thread copper tubes aluminum fins

and stainless steel frame. The two condenser fans draw ambient air through the condenser coils.

Each condenser rejects heat to the ambient air from the high temperature refrigerant gas which

has been pumped from the compressor. When heat is rejected from refrigerant to the coil, gas

cools and condenser into a liquid refrigerant.

Fig 5.4 Condenser Fans

Filters:The air conditioning unit has two kinds of filters-

Fresh air filter: They are placed inside the fresh air intake of the unit

Return air filter: they are placed in the ceiling panel above the return air intake to return air

duct. They are placed in this position so that no unfiltered air will enter the unit and duct system

Emergency Inverter:

In the event of 415V on-board supply failing, cooling of passenger saloon is no longer possible.

Therefore in order to maintain the supply of fresh air to the passenger compartment, an

emergency inverter is mounted inside the HVAC unit is activated.110V DC taken from the

battery is converted into 52V AC, which is further converted into 415V AC using step up

transformer and this 415V is used to run evaporator fan only

5.5 AIRCON WORKING MODES

The saloon air-conditioning works in the following modes

Ventilation Mode: In this mode air to be circulated throughout the vehicle and at the

same time fresh air will continually be induced into the vehicle but cooling will not be

initiated.

Cool 1: During Cool 1 the air conditioning unit provides approximately 50% of the total

rated cooling capacity. This is carried out by operating compressor and energizing only

one of the liquid line solenoid valves which allows refrigerant to flow into the evaporator

.Cool 2: During cool 2 modes the air conditioning unit provides 100% of the total rated

cooling capacity. This is carried out by operating and fully loading the semi-hermetic

compressor and energizing both of the liquid line solenoid valves which delivers

refrigerant to the evaporator coil.

Emergency Mode: In case of Ac Power supply failure the aircons shift to the

emergency vent mode. The power is supplied by the battery and only fresh air is supplied

into the saloon.

CHAPTER 6

Visual system

6.1 PASSENGER INFORMATION BOARD (PIB)

Fig 6.1 Passenger information board

Location:

There are three PIB’s installed in each passenger saloon. All three are powered from the train

battery 110V DC supply and continues to operate when traction power is lost.

Function:

The main function of the PIB’s is to provide information to the passengers. The PIB provides the

following information:

1. Next station is …. - inside train, on the PIB’s

2. This station is … - inside train, on the PIB’s

3. Journey message …..inside train, on the PIB’s

4. Real time information (visual only) - inside train, on the PIB’s (generated by OCC)

The Passenger Information Board (PIB) has a display matrix 32 (H) x 160(W) pixels. Both

Hindi and English messages can be scrolled on the display simultaneously and in synchronism.

It is recommended that for the automatic route announcements Hindi Characters are displayed in

yellow and the English characters in green. EMERGENCY TALK BACK UNIT (ETU) &

PASSENGER ALARM BUTTON

6.2 ETU &PAB

ETU PAB

Fig 6.2 Emergency talk back unit & Passenger alarm button

In case of emergency if a passenger wants to talk to the driver he can do so with the help of ETU

i.e. EMERGENCY TALK BACK UNIT and PAB i.e. PASSENGER ALARM BUTTON.

The PAB is installed at each passenger exterior doorway. There are four PAB’s in each vehicle,

associated to doors L1 L2 R1 and R2. ETU is installed at each door position, with the

microphone/loudspeaker positioned approx 1.5m from the vehicle floor. We have four ETU’s in

each car. It is provided as an interface between the passenger and the driver. The Passenger can

talk to the driver through the ETU. As soon as the passenger presses PAB, ETU detects that PAB

has been operated, and will identify this condition to the PAMP. The PAMP then send signal to

AVAU which further informs the driver by sending information at MOP. Now driver is ready to

talk to the passenger. The position of that particular ETU is also displayed on MOP. The large

red circular button is mechanically latched and is reset by inserting and turning a square Carriage

Key in a clockwise direction. The button is red in colour, having a central part with the square

key-hole; this central part is silver in colour.

ETU is installed at each door position, with the microphone/ loudspeaker positioned approx.

1.5m from the vehicle floor. The ETU shall identify when a PAB has been activated.

Flow diagram:

PAB ETU PAMP AVAU MOP

Fig 6.3 Flow diagram of ETU

Loudspeaker & 100V line transformer

The loudspeaker can be driven with 4Watts of power, provided by the PAMP over the 100V line

distribution system.

Location:

It is installed with 6 sets in each saloon.

CHAPTER 7 PASSENGER SALOON DOOR

7.1 INTRODUCTIONThe passenger saloon door system comprises electrically powered, double leaf, sliding doors

designed to permit safe entry and exit for passengers from the train cars.

Location:

Five door sets are located along each side of each "DT," "M," "M," and "DT" car.

Function:

The door system is designed to permit safe entry to and exit from the train cars. The door system

is also designed to prevent entry or exit from the train when the train speed exceeds 5 km/h.

Passenger and crew safety is maintained at all times. The doors provide for physical, thermal

and acoustic separation from the external environment. All bodyside doors include emergency

access systems that are operated manually.

Fig 7.1 Passenger Saloon Doors Position Numbering-Complete Train Set

Design and performance details:

a) To allow clear passage through an area of 1400 mm wide by 1900 mm high for each

saloon door, or 600 mm wide by 1920 mm high for each cabin door.

b) To permit safe entry to and exit from the train cars.

c) To prevent entry or exit from the train when the train speed exceeds 5 km.

d) To maintain passenger and crew safety at all times.

e) To not cause injury to passengers, crew or other person under normal operating

conditions.

f) Prevent ingress of dust and water.

g) To include emergency access systems that are operated manually.

h) The internal emergency release handle can be used to open doors while the train is in

motion.

i) To enable control and reporting of door actions and status to the TIMS through the DCU.

j) To allow adjustment of the door forces via a laptop computer connected to the DCU, or

by the TIMS in special LDR mode.

k) To not exceed an opening force of more than 150 N.

l) To open in a standard time of 2 to 2.5 seconds.

m) To close in a standard time of 2.5 to 3.5 seconds (at 110 V DC)

TYPES:

Four types of door system are provided for the train. These are:

TYPE LOCATION

Passenger body side door system. Each side of each "DT", "M" "M" and "DT"

car, making a total of 8 door sets per car.

Cabin body side door system. Each side of the driving cabin in the "DT" car.

Emergency door system Front of each driving cabin in the "DT" car.

Partition door system Between each driving cabin and the saloon in the "DT" car.

Table 7.1: Types of door system and its location

7.2 MAJOR COMPONENTS

The major components of saloon door system are as under:

1. Door Panel

2. Door Control Unit

3. Door Gear Assembly

4. Door Locking Mechanism

Fig 7.2 Components of Metro door

7.3 Passenger Door System Major Components

Door Panels:

Door panels are of aluminum composite construction bonded using aerospace technologies. Two

No of door panels (LH/RH) are provided in each door

.

Door Control Unit:

The Passenger Saloon Door operates electronically, via the electronic Door Control Unit (DCU),

except when the manual emergency release mechanism is used. The DCU activates door

opening and closing on receipt of signals from the train operator's panel. Door status signals,

such as "Door Open" and "Door Closed and Locked" are returned from the DCU to the train

operator’s panel. In all instances, the DCU controls whether the door can be opened or not. The

door can be manually opened, or closed and locked, regardless of whether power is available.

Door Gear

The Door Gear Assembly consists of:

Mainframe Assembly: The Mainframe Assembly is located at the top of each External

Slider Door system. This is the primary fixing point for mounting the door assembly into

the car body.

Electric Motor and Gearbox: The electric motor provides power for movement of door

panels. Motor used is a permanent magnet dc motor.

Fig 7.3 Door gear

Major Components

Transmission Belt and Transmission Pulley: The transmission belt and pulley transmits

the motor movement to the spindle shaft. The transmission pulley is mounted on spindle

shaft.

Spindle Shaft: On the movement of pulley spindle shaft rotates and transfer the

movement to the drive brackets via spindle nuts.

Drive Brackets: Door brackets are mounted on door panels.

Fig 7.4 Drive brackets

Solenoid and Door Lock: The Locking Mechanism is integrated in the Door Gear

Assembly in centre of the Door Gear Assembly. Mechanical locks are used to ensure full

locking. The centre hook assembly locks the Doors as they meet in the centre. A Lock

Switch mounted onto the Door Gear Assembly is activated by the Centre Hook Assembly

to signal the Door Control Unit that the door is locked.

Door Isolation Switch Assembly: Door isolation switch assembly is provided in the

middle of door gear assembly. It is used to isolate the door in case of any door failure.

Emergency Release Mechanism: Emergency release mechanism is provided to open

the any particular doors without opening all doors in case of any emergency. In every car

door no 2 and door no 6 are provided with external emergency release device. Internal

emergency release devices are provided in all cars.