This is based on Brakes & Pneumatics system used in DMRC

1. Study of Brakes and Pneumatic System in Rolling Stock
Under the supervision of
Mr. Neeraj Singh (Manager,Rolling Stock)
Submitted By:
B.tech (Mechanical Engg)
(10th june 2019 to 5th july 2019)

2. 1
ACKNOWLEDGEMENT
RAHUL RAI
(Roll No.03415611116)

3. 2
OBJECTIVE
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4. 3
ABSTRACT

5. 4
INDEX
Acknowledgement
Objective
Abstract
Chapter-1: DMRC & its Rolling Stock……………………………………………………………………………….….5
1.1 Introduction…………………………………………………………………………………………………………….........5
1.2 Board of Directors…………………………………………………………………………………………………………...6
1.3 Lines & Depots………………………………………………………………………………………………………………...7
1.4 About Najafgarh Depot………………………………………………………………………………………………..…10
1.5 About Sultanpur Depot………………………………………………………………………………………………..….11
1.6 Comparison Of both depot……………………………………………………………………………………………...12
Chapter-2: Rolling Stock In Brief………………………………………………………………………………………...13
2.1 Introduction…………………………………………………………………………………………………………………....13
2.2 Operating Parameters……………………………………………………………………………………………………..14
Chapter-3:Bogie,Wheel & Suspension………………………………………………………………………………...15
3.1 Introduction…………………………………………………………………………………………………………………….15
3.2 Components…………………………………………………………………………………………………………………...15
Chapter-4:Brakes & Pneumatics…………………………………………………………………………………………20
4.1 Introduction…………………………………………………………………………………………………………………..…20
4.2 Types Of Brake………………………………………………………………………………………………………………….20
4.3 Pneumatic Air Distribution System……………………………………………………………………………………22
4.4 Brake Control Equipment………………………………………………………………………………………………….24
Chapter-5: Doors & its Operation……………………………………………………………………………………….27
Chapter-6:HVAC System……………………………………………………………………………………………………..31
Conclusion…………………………………………………………………………………………………………………………..32

6. 5
1.DMRC and its Rolling Stock
(commuting experience in Delhi metro to be customers delight)
1.1 Introduction:
The Delhi Metro has been instrumental in ushering in a new era in the sphere of mass urban
transportation in India. The swanky and modern Metro system introduced comfortable, air conditioned and
eco-friendly services for the first time in India and completely revolutionized the mass transportation
scenario not only in the National Capital Region but the entire country.
Having constructed a massive network of about 373 Km with 271 stations in record time in Delhi, NCR, the
DMRC today stands out as a shining example of how a mammoth technically complex infrastructure project
can be completed before time and within budgeted cost by a Government agency.
The Delhi Metro Rail Corporation Limited (DMRC) was registered on 3rd
May 1995 under the Companies
Act, 1956 with equal equity participation of the Government of the National Capital Territory of Delhi
(GNCTD) and the Central Government to implement the dream of construction and operation of a world-
class Mass Rapid Transport System (MRTS).
The DMRC opened its first corridor between Shahdara and Tis Hazari on 25th
December, 2002.
Subsequently, the first phase of construction worth 65 kilometres of Metro lines was finished two years and
nine months ahead of schedule in 2005. Since then the DMRC has also completed the construction of
another 125 kilometres of Metro corridors under the second phase in only four and a half years.
Presently, the Delhi Metro network consists of about 373 Km with 271 stations. The network has now
crossed the boundaries of Delhi to reach NOIDA and Ghaziabad in Uttar Pradesh, Gurgaon, Faridabad,
Bahadurgarh and Ballabhgarh in Haryana. With the opening of the Majlis Park to Shiv Vihar and Janakpuri
West - Botanical Garden Sections, new age trains equipped with the Unattended Train Operation (UTO)
technology have been introduced. These trains operate with the Communication Based Train
Control(CBTC) signaling technology which facilitate movement of trains in very short frequencies. This
network also includes the NOIDA - Greater NOIDA Aqua Line. The Aqua Line has been constructed by
DMRC on behalf of the NOIDA Metro Rail Corporation and is also being operated by DMRC currently. In
addition, the 11.7 kilometre long Rapid Metro also connects with the Delhi Metro network at Sikanderpur
station of Yellow Line. The Rapid Metro provides connectivity within the satellite city of Gurugram.
The Airport Express link between the Indira Gandhi International Airport and New Delhi has now propelled
Delhi to the league of global cities which have high speed rail connectivity between the city and the airport.
The DMRC today has over 300 train sets of four, six and eight coaches.
The Delhi Metro has also contributed tremendously on the environment front by becoming the first ever
railway project in the world to claim carbon credits for regenerative braking. DMRC has also been certified
by the United Nations (UN) as the first Metro Rail and Rail based system in the world to get carbon Credits
for reducing Green House gas emissions as it has helped to reduce pollution levels in the city by 6.3 lakh
tons every year thus helping in reducing global warming.
It has also set up roof top solar power plants at many of its stations. All stations of the presently under
construction corridors are being constructed as green buildings. In the present phase of Delhi Metro’s
construction, the DMRC is nearing the completion of 160 kilometres of Metro lines which has woven a web
of Metro corridors along the city’s Ring Road besides connecting with many other localities in NOIDA,
Ghaziabad, Bahadurgarh and Ballabhgarh.
Apart from providing Delhites with a comfortable public transport option, the Delhi Metro is also contributing
significantly towards controlling pollution as well as reducing vehicular congestion on the roads.

7. 6
1.2 BoardofDirectors:
Shri Durga Shanker Mishra Chairman, DMRC Ltd. & Secretary Ministry of Housing
and Urban Affairs
Shri Mangu Singh Managing Director, DMRC Ltd.
Shri Tarun Kapoor Director DMRC Ltd. & Vice Chairman
Shri K. Sanjay Murthy Director DMRC Ltd. & Additional Secretary(W&H) M/o
H&UA
Shri Mukesh Kumar Gupta Director DMRC Ltd. , Additional Member(Works),
Railway Board
Shri Ramesh Chandra Director DMRC Ltd.
Shri Som Dutt Sharma Director(Buisness Development), DMRC Ltd.
Shri Dinesh Kumar Saini Director(Project Planning), DMRC Ltd.
Shri K.K. Saberwal Director(Finance), DMRC Ltd.
Shri Daljeet Singh Director(Works), DMRC Ltd.
Shri Sudhanshu Shekhar Joshi Director(Rolling Stock), DMRC Ltd.
Shri A.K. Garg Director (Operation), DMRC Ltd.
Shri O. H. PANDE Director(Electrical), DMRC Ltd.
Ministry of
Housing &Urban
Affairs
Chairman
Managing Director Board Of Directors
Executive
Directors
HODs Deputy HODs
Manager/Assistant
Manager
SSE/SE/ASE/JE

8. 7
1.3LINESANDDEPOTS:
Currently DMRC has 12 depots:
1. Najafgarh Depot
2. Shastri Park Depot
3. Vishwa Vidyalaya -Khyber Pass Depot
4. Yamuna Bank Depot
5. Mundka Depot
6. Sarita Vihar Depot
7. Sultanpur Depot
8. Dwarka Sector 21 Depot
9. Kalindi Kunj Depot
10.Mukundpur Depot
11.Vinod Nagar Depot
12.Ajronda Depot

9. 8
There are 8 lines in Delhi Metro. These are:
RED LINE YELLOW LINE
(From Shaheed Sthal to Rithala) (From Samaypur Badli to Huda City Centre)
Length -34.69 km Length -49.31 km
BLUE LINE GREEN LINE
(From Noida Electronic City to Dwarka sec -21) (From Inderlok to Shaheed Hoshiyar Singh)
(From Yamuna Bank to Vaishali) (From Ashok Park Main to KIrti Nagar)
Length -56.61 km Length -26.32 km
Length -8.74 km Length -3.32 km

10. 9
VIOLET LINE MAGENTA LINE
( From Kashmere Gate to Raja Nahar Singh) (From Botanical Garden to Janakpuri West)
Length -46.63km Length -37.46 km
PINK LINE ORANGE LINE
(From Majlis Park to Mayur Vihar Pocket -1) (From New Delhi to Dwarka Sec. 21)
(From Trilokpuri Sanjay Lake to Shiv Vihar)
Length -39.72 km Length -22.70 km
Length -17.86 km

11. 10
Najafgarh Metro Depot is one of the two depots present on the Line 3(Blue Line) of Delhi Metro Rail
Corporation (DMRC). Line 3 consists of Rolling Stock 1 and Rolling Stock 2.
It is the depot with all the facilities:
1. Inspection Bay Line: It is the workstation where trains are diagnosed and faults are
detected and corrected. Here work can be done on underframe ,saloon interior or on roof.
2. Stabling Bay Line: It is the workstation where trains are kept stable. We can work on the
outer body except the underframe. Major work like cleaning the saloon and checking of doors
can be done and rectified.
3. Workshop: It is the workstation where all the electrical and mechanical repairs are done, if
some parts need to be opened or replaced then its done here.
4. Auto Wash Plant: It is the workstation where trains are washed and dried automatically.
While cleaning trains move at a speed of 5 km/hr.
5. Progressive Planning Inspection Office: In this office all the planning and scheduling are
done for trains . Without its permission no work can be done.
6. Depot Control Centre: It controls the movement of trains inside the depot.
7. Pit Wheel: It contains lathe machine for profiling wheels.
8. Test Track: These are special tracks in depot for testing of newly arrived coaches and
repaired coaches.

12. 11
Najafgarh Depot has 40 SBLs, 6 IBLs, 6 WSLs, 2 Shunting Neck and a total area of 52
hectare.
Sultanpur depot is also one of the two depot on Line 2(Yellow Line) of Delhi Metro Rail
Corporation. This depot deals with only RS -2 bogies . This depot has 13 SBLs, 3 IBLs, and
two watching towers. This depot does not have workshops and it has one Shunting Neck.

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Najafgarh Depot Sultanpur Depot
1. Present on Line 3(Blue Line) 1. Present on Line 2(Yellow Line)
2. Deals with maintenance of RS-1 & RS-2 2. Deals with maintenance of RS-2
3. Have a very large area (52 Hectare) 3.Have small area
4. Have 40 SBLs 4.Have 13 SBLs
5. Have 6 IBLs 5.Have 3 IBLs
6. Have 6 WSLs 6. Does not have any workshop
7. Have 2 Shunting neck 7. Have only 1 Shunting Neck

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2.Rolling Stock In Brief
2.1 Introduction
Train Consists: One train set consists of 4 cars/ 6 cars/ 8 cars. Three types of cars (DT, T &
M) are used to form a train set. At each end is a "DT" car which is a trailer car with driver’s cab and
pantograph. The other type is an "M" car, which is a motor car without pantograph. The train is
provided with an Automatic Train Protection (ATP) / Automatic Train Control (ATC) function to
protect the train and initiate emergency braking under specific conditions.
With increase of passenger traffic, the number of cars in a train can be increased from 4 cars
to eight cars. A pair of trailer & motor cars (DT-M or T-M) is called a ‘unit’. These units are coupled
by automatic coupler and can be uncoupled very easily. Unit (DT-M) can be moved independently by
self power.
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

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DT Car (Driver Trailer Car) :The cab end of each "DT" car is fitted with an automatic coupler that
is compatible with the locomotives couplers.
M Car (Motor Car) :The "M" car is fitted with one automatic coupler at the position of M-car
connection and one semi-permanent coupler at the position of DT-car connection.
2.2 Operating Parameters:

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3.Bogie, Wheel & Suspension
3.1 Introduction
A bogie is a component found in all types of trains( locomotive, wagon, metro, tram,
etc. ) .A bogie is a frame, placed under the trains, onto which the wheels of the railway
vehicle are fixed .As bogies are mobile in relation to the frame of the vehicle itself , they
can notably be used to facilitate movement on curved tracks.
Purpose
Bogie serve a no. of purposes:
 Support of the rail vehicle body
 Stability on both straight and curved track
 Improve ride quality by absorbing vibration and minimizing the impact of centrifugal
forces when the train run on curves at high speed
 Usually two bogies are fitted to each carriage, wagon or locomotive, one at each end
3.2 Components of Bogie
The important component of bogie are:
 Wheel Sets
 Bogie Frame
 Primary & Secondary Suspension

17. 16
 Centre Pivot Device
 Traction Motor
 Driving Gear & Gear Coupling
 Bogie mounted friction Brake equipment
3.2.1 Bogie Frame: The bogie frame is “H” or “I” shaped fabricated frame construction with two
side frames and one transom. The side frame provides the mounting support for the air spring assemblies
and Primary spring assemblies. The transom area incorporates mountings for the brake equipment, driving
gear mounting brackets, traction motor mounting brackets, the mono-link mounting bracket.
1. Motor bogie frame - The transom area incorporates mountings for the brake equipment, driving
gear mounting brackets, traction motor mounting brackets, the mono-link mounting bracket.
2. Trailer bogie frame - The transom area incorporates mountings for the brake equipment, the
mono-link mounting bracket and ATC beacon antenna mounting bracket is bolted to the transom of front
bogie.

18. 17
3.2.2 Centre Pivot Device: Mono-linkage type Centre Pivot Device forms the main connection
between the bogie and the carbody. This allows for full movement of the bogie (lateral, vertical, yaw and
pitch) with respect to the body structure but restricts the longitudinal displacement between the bogie and
car body.
3.2.3 Wheelset: Trailer and motor wheels have identical. Diameter of wheel is new wheel 860mm and
fully worn wheel 780mm. Minimum thickness of flange measured from wheel gauge face at 13mm from outer
edge of flange = 22 mm . Maximum projection for flange of worn wheel measures from the tread at 63.5mm
from the wheel gauge face = 35mm.
3.2.4 Axle: Motor and trailer bogie axles are similar, except the motor bogie axles have additional
mounting seats for the gearbox. All the components are a shrink fit onto the axle. Because of the integral
gearbox fitted to the motor bogie, motor and trailer axles are not interchangeable.
3.2.5 Driving Gear & Coupling: The driving gear is mounted on both of the transom and the power
motor axle. The power is transmitted from the motor to the gearbox by means of a torsionally rigid but
flexible gear coupling.

19. 18
The flexible gear coupling consists of two half couplings connected with bolts. One is fitted into the traction
motor shaft and another is fitted into the driving gear shaft. The traction motor and the driving gear are
mechanically connected by a flexible gear coupling, through which the torque is transmitted to the power motor
3.2.6 Block Brake Unit: The brake block unit assemblies are provided for application of pneumatic
brakes. One block brake unit is provided on every wheel. Block brake unit are combinations of a brake cylinder,
a transmission mechanism and a slack adjuster. The parking block brake unit has an attached spring actuator.
There are two types of brake block unit of with parking brake and without parking brake as a main friction
brake system on the each bogie, which are located diagonally on the Motor and Trailer bogie as same position.
3.2.7 Secondary Suspension System: The secondary suspension system on the bogie is provided
with two principal aims.
 To ensure good ride quality.
 To ensure the vehicle floor height remains equal in all riding conditions
In achieving these aims, air secondary suspension springs are used as the main vertical suspension system
between the bogie and the carbody.
The main parts of secondary suspension are as under –

20. 19
I. Air Spring II. Leveling Valve III. Anti roll Bar
3.2.8 Primary Suspension: The primary suspension is located between the bogie frame and journal
box. The primary suspension is of conical rubber spring type. The conical spring serves vibration and noise
reduction and damping. The conical rubber springs take all loads applied to the wheel set by braking,
acceleration, curve riding, guiding by the rails and passenger load.

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4.Brakes & Pneumatics
4.1 Introduction
Brakes are used to slow or completely stop the motion . Delhi metro uses the pneumatic
system to apply the brake that is with the help of air pressure and they are regenerate
the electricity with the brakes . So, DMRC use the brake with its benefit in economical
manner.
4.2 Types of Brake
1. Service Brake: Electric Regenerative brake and Electro-Pneumatic (EP) friction brake blending,
Load weighed and Jerk Controlled
2. Emergency Brake: EP friction brake, Load weighed
3. Parking Brake: Spring applied, air-release parking brake
4. Holding Brake: EP friction brake
5. BP (Brake pipe)-back up brake: Pneumatic friction brake
4.2.1 Service Brake: Priority of braking effort;
- Electric Regenerative brake controlled by C/I of Motor car
- EP friction brake controlled by BECU of Driving trailer car
- EP friction brake controlled by BECU of Motor car (In the beginning and end of service braking)
- EP friction brake of Driving Trailer car & Motor car (In case of failure of electric brake)
4.2.2 Emergency Brake: It is applied in case of failure, danger and emergency. The train
set is equipped with an emergency brake loop wire. The emergency brake loop is connected to the
emergency brake magnet valve, which is opened when de-energized and closed when energized (Fail-
safe system). So, in case the emergency brake magnet valve is de-energized by interrupting
emergency brake loop, the emergency brake will be applied automatically.
4.2.3 Holding Brake: The holding brake is provided to prevent the train from rolling
backwards on a rising gradient and the train from moving at the station.
4.2.4 Parking Brake: Parking brake is used for parking the train in depot and these are
installed at Driving trailer car and Motor cars (1 set per axle). It is present diagonally opposite to

22. 21
each other in one bogie (axle). To release the parking brake there is lever present underframe close
to wheels when we pull it , it release the parking brake.
4.2.5 Load weighing: The load dependent pressure limiting valve is used to limit the supply
reservoir air pressure according to the actual car load. Becoz at the same time the load on each bogie
is not the same . At the same time the average load signal is electrically fed to the BECU from the T
pressure transducer on the EP-BCU. This signal is used for load compensation of the propulsion and
airconditioning system.
4.2.6 Wheel Slide Protection: Wheel slide protection is used to optimize the stopping
distance and to avoid the wheel flats under wheel sliding conditions. Wheel slide protection is active
in service brake and emergency brake. In this we check the rpm of all the axle in each bogie & then if
we find that there is sudden drop in rpm of any axle then immediately we release the brake pressure
f that axle. It is also called anti skid control.
4.2.7 BP-back up Brake: Additional BP (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.
By the brake valve the brake pipe (BP) pressure can be reduced or increased depending on the
time the brake lever is maintained at “braking” or “driving”. During the normal service brake
operation, the drivers brake valve lever shall be maintained at “driving.

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4.3 Pneumatic Air Distribution System
4.3.1 Main Compressor: The compressor is a cylinder piston compressor(VV120) powered
by a 415 V AC, 50Hz motor and it has a capacity of approximately 900 L/min free air at 10 bar.
In normal service operation the air compressors of each DT car is controlled individually by the
relevant BECU at that trailer car. The BECU in turn communicates with all other BECU installed in
the train consist to determine which air compressor should be operated.
4.3.2 Air Dryer & Filtration: Moisture in compressed air systems often causes the
pneumatic equipment to malfunction and wear prematurely as a result of corrosion and freezing. The
compressed air supplied by the main air compressor is filtered by oil separator and dried by the air
dryer unit and filtered by the oil micro filter. The air dryer unit consists of two chambers with a
adsorptive desiccant. While the main air flow is being dried in one chamber (I), the desiccant of the
other chamber (I) is being regenerated by the reversed air flow.
4.3.3 Main Reservoir: Air supply system is provided with main air reservoirs (A7) with a
capacity of 200 liters & located in each DT Car.

24. 23
4.3.4 Isolating Cock: It is possible to isolate the compressed air supply system to the
consumers such as air suspension equipment, pantographs, air horns and automatic couplers by
operating the isolation cocks with/ without a vent and an electrical switch. The isolation cocks with/
without a vent and an electrical switch are located on the under frame adjacent to the bogie.
4.3.5 Single Protection Valve: The single protection valve (B26) is installed in front of
the main reservoir (MR) air hose of each end of the car. The valve shuts off the air supply through
the hose in the event of a break or damage to the hose or the main piping, maintaining the main
reservoir air pressure in the system.
4.3.6 Auxiliary Air Distribution System: In the event that the MR pipe is not
charged, the required air pressure for pantograph operation is supplied by the auxiliary motor-
compressor unit (U01). The unit includes a single-stage compressor driven by a 110 VDC motor.

25. 24
4.4 Brake Control Equipment
4.4.1 Brake Electronic Control Unit: The BECU commands the brake system and
implement anti-skid functions by evaluating the set points for the brake value out of various input
signals (e.g. brake demand signals, speed signals or load signals.) BECU calculates the required brake
force according to brake demand and send electrical signal to the BCU. Every car has its individual
BECU.
The BECU consists of the following Cards:
1. MB04B Card - MB04B is a main board. It is loaded with application software. It consists of a
main board MB03B and a man machine interface (MMI).
2. EB01B Card- The board is used to enhance the input and output operations of the main board.
3. CB07A Card - CB07A is a communication board in the ESRA system.
4. PB03A Card - PB03A is used to power the BECU. It meets the demands of both the
electronic boards and the sensors and actuators.
4.4.2 Brake Control Unit: One pneumatic brake control unit (B3) is provided in every car.
The BCU has following main components :
a. Analog Converter
b. Emergency Brake Valve
c. Double Check Valve
d. Pressure Transducer
e. Load Limiting Valve
f. Relay Valve
The analogue converter in converts the electric friction brake demand signal from the BECU (B15)
into a proportional pre-control pressure (Cv).
The relay valve provides a large volume air flow a the specific pressure level, pre-controlled by the
analogue converter, to actuate the brake cylinders.

26. 25
The Cv-pressure sensor is used to indicate the emergency brake pressure level generated by the
emergency brake magnet valve (system pressure 8 to 10 bar).
The double check valve is used to change-over between normal service brake and back-up brake
operation by the distributor valve type STV (B41).
The isolating cocks with electrical switch in the brake cylinder pipe isolate the brake per bogie and
allow the air-applied brake cylinders to be released on a per bogie basis.

27. 26

28. 27
5.Doors & its Operation
5.1 Introduction
A door in a train is a panel or barrier, usually hinged or sliding, that is used to cover an
opening in a train.Exterior doors are doorways that allows entrance to or exit from a train.
The door system permits safe entry to and exit from the train cars. Also, the doors
provide physical, thermal and acoustic separation from the external environment.
Four types of door system are provided for the train. These are:
(a) Passenger or saloon door system.
(b) Cab door system.
(c) Emergency door system.
(d) Partition door system
1. Passenger Saloon Door: The passenger saloon door system comprises electrically
powered, double leaf, sliding doors designed to permit safe entry and exit for passengers from the
train cars.
Components: The major components of saloon door system are as under
1. Door Panel
2. Door Control Unit

29. 28
3. Door Gear Assembly
4. Door Locking Mechanism
5. Emergency Release Mechanism
6. Door Isolation Switch
Door Operation: The operation of the passenger saloon door system is controlled by Door
Control Unit that interfaces with the Train Integrated Management System (TIMS).
On receipt of an open command from the DCU, the door locking system unlocks the door and
the door operating mechanism slides the door panels to their open position. Close limit switch and
Lock limit switch attached to the door operating mechanism, notify the DCU whether the door is
closed and locked or not.
2.Cab Door: The function of the cab or driver’s door is to provide access to the cab for
the driver.Only DT-car is equipped with two cab doors.The cab door is of sliding type.

30. 29
Door Function: The door system is designed to permit safe entry to and exit from the train
cars. The doors provide for physical, thermal and acoustic separation from the external environment
Door Operation: The cab side door operates manually. Door status signals, such as "door
open" and "door closed and locked" are returned from the limit switches to the TIMS.
3. Partition Door:The partition door is a hinged double door located between the cab
area and the saloon area in each “DT” car.
Operating Principle: The partition door is operated manually from the saloon or cab in
the following situations:
(a) Normal Situation
(i) From Cab =The secondary leaf is opened into the cab by the operation of a handle on the door
leaf. (ii) From Saloon =The secondary leaf is opened by a KABA key.
(b) Emergency Situation -In the event of an emergency, both the door leaves (master leaf and the
secondary leaf) are opened into the cab by pushing out an emergency access panel on the master leaf
and then operating the door handle on the cab side through the opening.
4. Emergency Door: The emergency door is manually operated for train-to-track
detrainment. The detrainment light and cabin main light automatically illuminate upon deployment of
the emergency door.
The emergency door is located in front of each “DT” car.

31. 30
Operation: To move crew and passengers from a defective train onto the track. In this
mode evacuation is accomplished down to track level. Emergency Door opens and deploys in such a way
that in its final position door becomes an emergency ramp that enables passengers to descend from
cab floor level down to track level.

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6.HVAC System
(Heating,Ventilation & Air-Conditioning System)
The function of a HVAC system is
• To achieve and maintain acceptable indoor climate in cab and saloon.
• To produce quality air for the driver and the passengers.
• To protect passengers and driver from smoke produced outside the train.
• To secure CO2 levels inside the train at the time of auxiliary power
failure.
Location of HVAC
• Two saloon HVAC units are mounted on the roof ends of each car.
 One cab HVAC unit is mounted on the roof, behind the cab

33. 32
Conclusion
It was a great experience for me to have opportunity of internship in DMRC as
through this I came to know so many things and practical exposure helps me to
have better understanding of what we have learnt.The members are very
dedicated & are always ready to help and to give any information. I am sure the
information and experience helps me a lot in future.
Studying and analysing the Braking System in DMRC was a great learning
exposure. I came to know about Bogies and suspension, then different types of
brakes and their functioning and the doors system. The overall learning is
fruitful and knowledge based.
The regular depot visit gave me a deep insight into the Braking System along
with other parts of rolling stock. During the training phase, I not only learn the
way of work in an organisation , but also the importance of punctuality ,
commitment and team spirit.