A project report on Train lighting and Air Conditioning in different type of coaches present at east coast railway Bhubaneswar.

1. CARRIAGE REPAIR WORKSHOP, MANCHESWAR
EAST COAST RAILWAY
SUMMER INTENSHIP REPORT ON TRAIN LIGHTING & AIR CONDITIONING
DURATION: - 01/06/2022 - 01/07/2022
SUBMITTED BY: -
SL. NO. STUDENT NAME NAME OF COLLEGE
1 SUBHAKANTA BARIK GIET, BHUBANESWAR
2 ABHIJEET PRADHAN OUTR, BHUBANESWAR
3 ABHISHEK SAMAL OUTR, BHUBANESWAR
4 ABINASH MOHAPATRA VSSUT, SAMBALPUR
5 SOMDYUTEE SUR ITER(SOA), BHUBANESWAR
6 AHKAM KHAN ABIT, CUTTACK
7 CHANDAN KUMAR BEHERA IGIT, SARANG
8 SOMYAPRAKASH MISHRA TRIDENT, BHUBANESWAR
GUIDED BY: -
MR. ASHOK NAHAK (CHIEF INSTRUCTOR, BTC)
MR. J. K. PATTANAIK (SSE, TL)
MR. GIRISH MISHRA (SSE, AC)

2. DECLARATION
We hereby declare that this project is being submitted in fulfilment of
the Industrial Training Programme in East Coast Railway
Carriage Repair Workshop, Mancheswar, Bhubaneswar, and is
result of self done work carried out by us under the various guidance
of engineers and other officers.
We further declare that to our knowledge, the structure and content
of this projected are original and have not been submitted before for
any other purpose.
GROUP – 2 (ELECTRICAL)
CARRIAGE REPAIR WORKSHOP, MANCHESWAR
EAST COAST RAILWAY

3. ACKNOWLEDGEMENT
The internship opportunity we had with Carriage Repair Workshop,
Mancheswar was a great chance for learning and professional development.
Therefore, we consider ourselves as very lucky as we were provided with an
opportunity to be a part of it. We are also grateful for having a chance to meet
so many wonderful people and professionals who led us though this
internship period.
We are using this opportunity to express our deepest gratitude and special
thanks to Mr. Ashok Nahak, Chief Instructor, BTC who in spite of being
extraordinarily busy with his duties, took time out to hear, guide and keep us
on the correct path and allowing us to carry out our project at their esteemed
organization and extending during the training.
We express our deepest thanks to Mr. V. Durgaprasad, Senior Instructor,
BTC for taking part in useful decision & giving necessary advices and
guidance and arranged all facilities to make life easier. We choose this
moment to acknowledge his contribution gratefully.
It is our radiant sentiment to place on record our best regards, deepest sense
of gratitude to Mr. J. K. Pattanaik, SSE(TL) and Mr. Girish Mishra, SSE(AC)
for their careful and precious guidance which were extremely valuable for our
study both theoretically and practically.
Last but not the least our sincere gratitude to all people who knowingly or
unknowingly supported us, to make this project a reality.

4. CONTENTS
Sr. No. Topic
1 Train Lighting
1.1 Systems of Train Lighting
1.2 Brushless Alternators
1.3 Rectifier cum Regulator Unit (RRU)
1.4 Batteries
1.5 Carriage Fan
1.6 Carriage Lighting
1.7 Maintenance Schedules
2 Air Conditioning
2.1 Description of Power Supply
2.2 AC Equipments in Railway Coaches
2.3 RMPU
2.4 Major Components of RMPU

6. 1. SYSTEMS OF TRAIN LIGHTING
Train lighting is one of the important passenger amenities which influence the image of
Railways. Power supply system for trains is designed and developed to suit the
requirement of AC and non-AC working in the trains.
SELF GENERATION (SG)
The power supply arrangement of SG coach has underslung alternator, which is
driven by the running axles of the coach with the belt of the coach. The voltage of the
alternator which varies with the speed of the train is regulated with the help of RRU and
converted to 110V DC and is used for charging the battery. The electrical load of the
coach is supplied through the 110V DC battery at the halt.
In AC coaches, two 25kW alternators are used in AC-2T/AC-3T /Chair Cars and
only one alternator is used in First AC coach.
In case of non-AC coaches, three phase output from 4.5 KW alternator mounted
on the bogie of coach is fed to the regulator cum rectifier for rectifying the AC output to
DC and regulating the output voltage at different speeds and loads. The output from
rectifier cum regulator on the underframe is brought through cables on the coach. The
load is fed through four rotary switches (RSW) and fuses connecting circuits LI, L2, F
and SPM. LI feeds the essential lighting load like lavatories, gangways, doorways and
upto 50% of light in each compartment/bays corridor lights and night lights, L2 feeds
remaining lighting loads, F feeds the fan load and SPM feeds emergency feed terminals
(EFT).
An external battery charging terminal (BCT) is provided to charge the battery from
external charger, if battery is in rundown condition due to failure of alternator.
Systems for Train
Ligthing
Self Generation
(SG)
Axle driven
system working
on 110V DC
End-on
Generation
(EOG)
750V AC, 3-phase
110V AC
utilisation
415V AC, 3-phase
110V AC
utilisation
Mid-on
Generation
(MOG)
415V AC, 3-phsae
110V AC
utilisation
Head-on
Generation
(HOG)
750V AC, 3-phase
110V AC
utilisation

7. MID-ON-GENERATION (MOG)
The MOG system was adopted by IR for slow-moving passenger trains which
have the very low generation to non-generation ratio. These trains had one power car in
the middle of the train, which fed power supply to the coaches at either side of power
car. The power car coach had two DA set of 30 KVA each out of which one was used as
standby. The power car coach also had one 3 phase, 30 KVA step down transformer of
415/110V. The 110V AC supplied to the coaches through couplers.

8. END-ON-GENERATION (EOG)
The EOG system is used in Rajdhani and Shatabdi type trains which have only
AC coaches and have large power requirement. Each EOG train has 2 power cars with
2*250kw alternator each. The power is fed by any two DA sets through IVC. The power
is supplied at 3 phase, 750V, which is stepped down in an individual coach to 3
phase,415v for supplying various loads like RMPU, WRA etc. The 110v AC supply for
lights and fans is obtained by further stepping down the 415v supply. A 24v battery is
used for supplying a few emergency lights provided in the coach.

9. HEAD-ON-GENERATION (HOG)
In HOG scheme, power is fed from the electric locomotive to the train to cater for
the Hotel Load of the train. In electric locomotives, power is taken from the OHE through
pantograph to traction transformer of the locomotive which is provided with a hotel load
winding of 945 kVA, at nominal voltage of 750V single-phase, which varies with the OHE
voltage variations. This 750V single-phase supply is fed to Hotel Load Converter, which
gives 750V 3-phase 50 Hz supply as output, for feeding the hotel load of the train.

11. 2. BRUSHLESS ALTERNATORS
Brushless alternators are axle driven, with ‘V’ belt drive, mounted on the bogies of
the AC & TL coaches. These alternators are of various ratings and make as per
requirement for different type of coaches.
The ratings in use are: -
i) 4.5 KW, 120V BG non-AC coaches
ii) 25 KW,130V, alternator for BG AC coaches (new)
4.5 KW ALTERNATOR
4.5 KW brushless alternator is of totally enclosed construction capable of
developing a constant voltage of 120V and is used for: -
i) Charging the coach battery.
ii) Operation of lights, fans in the coach.
CHARACTERISTICS OF 4.5 KW ALTERNATOR
Output 4.5 KW
Voltage 120V DC
Current 37.5 A
Cut in speed 350 RPM (Approx. 19 KMPH)
MFO 600 RPM (Approx. 31 KMPH)
Max speed 2500 RPM (Approx. 130
KMPH)
Mounting Transom Mounted
Drive V belts (4)

12. Alternator is mounted on the bogie or suspended from bogie. Bogie mounting is
called "Transom-mounting" and suspension from bogie is called "under-frame
mounting". All new 110V coaches have transom mounted alternators.
A suitable belt tensioning arrangement is also provided to adjust belt tension as
required.
Two sets of safety chains are provided to support the alternator and prevent its
falling on track while on run, in case of breakage of suspension pin.
25 KW ALTERNATOR
25 KW alternator is used for AC coaches. The alternator with associated regulator
delivers 25KW (at a constant voltage of 135+/- 5% from no load to 193A) at all train
speeds above 50KMPH. Two machines are used for Ac 2T/chair cars and one machine
is used for IAC coach for:
a) Charging the coach battery consisting of 56 cells of 800 AH capacity (1100 AH in
new coaches).
b) Supplying the coach loads like compressors, lights and blowers.
CHARACTERISTICS OF 25 KW ALTERNATOR
Output 25 KW
Voltage 135V ± 5% DC
Current 193A (Max)
Cut in speed 550 RPM (Approx. 30 KMPH)
MFO 930 RPM (Approx. 51 KMPH)
Max speed 2800 RPM (Approx. 130 KMPH)
Drive V belts (12)

13. 3. RECTIFIER CUM REGULATOR UNIT
(RRU)
The rectifier cum regulator unit has mainly following functions: -
i) To rectify the 3 phase AC output of the alternator through DC full wave bridge
rectifier.
ii) Regulating the voltage generated by the alternator at the set value.
iii) Regulating the output current.
In these SG coaches, magnetic amplifier controlled Rectifier cum Regulator Units
(RRUs)are used initially to convert AC output of alternator into DC and regulate/ control
the DC voltage generated through the regulation of the field current of the alternator.
This also prevents the reverse flow of current from battery to alternator during periods of
non-generation.
Since the working of RRU is based on magnetic core saturation, the voltage and
current ripple in the 110V DC output are varying substantially depending upon the type
of load and speed which may affect performance and life of VRLA batteries. Hence, it is
felt necessary to go for an alternative better design having fast response, better
regulation (within ± 2%) using fast switching devices with its control circuitry to achieve
higher reliability and fail safe feature of the equipment.
The objective of the development of IGBT based Electronic Rectifier cum
Regulator (ERRU) was primarily to regulate the alternator generation at the desired
setting considering the load condition and to maintain a constant charging current for the
battery and to reduce voltage as well as current ripple.
SALIENT FEATURES OF ERRU: -
i) High performance 16bit or above microcontroller used to ensure real time
response.
ii) Use of intelligent control algorithm for improved performance.
iii) Total CMOS design for low power consumption and reliability.
iv) Excellent DC voltage regulation.
v) Reduction of the ripple content in the controlled DC output.
vi) Better current regulation and current ripple.
vii)Reduction of cut-in and MFO speed for better power management.

14. BLOCK DIAGRAM OF ALTERNATOR-ERRU SYSTEM

15. ERRU circuits may be divided into five parts: -
1. Power Circuit: -
• 3 phase AC output supply from alternator is converted into DC voltage by power
rectifier consists of Isopack power diodes.
• Filtered dc output current is sensed by load hall sensor and battery current is
sensed by battery hall sensor.
• DC output voltage is available at DC+ and DC- terminals for roof load and B+
and DC-for battery charging.
2. Field Circuit: -
• DC supply required for field excitation is drawn from alternator and rectified.
• Field supply is controlled by UVC unit.
• UVC controls the field current to maintain the set output voltage of alternator.
3. Voltage Control Circuit: -
• The circuit consists of SMPS unit, micro controller and PWM generator.
• If the voltage exceeds preset value, the micro controller gives signal to gate of
IGBT.
• IGBT is fast switching device controls output voltage and maintain within
limits.
4. Current Sensing Circuit: -
• Whenever current exceeds preset value, the microcontroller gives signal to
gate of IGBT.
• IGBT controls output current and maintains within limits.
• Hall sensor used to sense the current flowing in the D.C. output of ERRU fed
into main circuit to limit the output current and protect the equipment from over
current.
5. Over Voltage Protection Circuit: -
• It is provided to stop the generation in case of any fault of the components
and cause over voltage.
• When over voltage exceeds 145 ± 1V OVP equipment disconnects the field
circuit and stops the alternator generation.

16. 4. BATTERIES
Earlier, conventional lead acid batteries were used for train lighting purposes. In a
charged lead acid cell positive active material consists of lead peroxide (PbO2) and the
negative of spongy lead (Pb). Dilute sulphuric acid (H2SO4 + H2O) serves as electrolyte.
The overall reactions inside the cell during discharge and charge are represented most
conveniently by a reversible equation as follows: -
PbO2 + Pb + 2H2SO4 ⇌ 2PbSO4 + 2H2O
Disadvantages of using conventional lead acid batteries: -
a) Necessity for frequent topping up cells:
Frequent topping up of cells in rake considering the unhygienic surroundings,
enormous quantities of distilled / demineralized water required, manpower
requirements for completion of topping up process in limited time, difficulties in
attending cells in rear row, spilling of electrolyte.
b) Leakages of electrolyte on lid and on container body:
During transit/handling/storage some cells develop fine cracks in container body and
result in leakages in services later on. Cases of spillage of electrolyte while topping
up the cells also occur.
c) Failure of one cell in Monoblock unit:
Cases of failure of one cell in 3 cell Monoblock unit have been occurring frequently.

17. d) Undercharging/Overcharging:
In case of unforeseen detentions, failure of regulator/alternator, undercharging
occurs. In day time, in winter, or in SLRs, the cells are likely to get overcharged if voltage
settings in the regulator is not properly adjusted. These features affect the life of battery.
VALVE REGULATED LEAD ACID (VRLA) BATTERIES
To overcome problems of frequent topping up, and leakage of electrolyte, sealed
maintenance free lead acid batteries, termed as SMF (VRLA) batteries have been
developed. Electrolyte in these batteries is in immobilized form and these can be used
in any position - horizontal or vertical.
Benefits
• Maintenance-free and spill-proof. This enables flexible mounting
• Wide operating temperature range (-40°C to +50°C)
• High energy density (gravimetric and volumetric)
• Good charge retention leading to long storage life
• Low internal resistance ensures quick recharge
• Excellent high-rate capability permits use of smaller capacity batteries
• Superior raw materials for good performance and life
• Excellent deep discharge recovery characteristics
Recombination Principle
The charge and discharge reaction of the lead acid battery can be expressed by the
following equation:

18. In a conventional flooded battery, towards the end of charge major part of the
energy supplied by charging is dissipated by electrolyzing the water in the electrolyte
generating Oxygen at the positive plate and Hydrogen at negative plate. These gases
are lost in a flooded system through the vent holes causing steady depletion of water
and therefore requiring periodic topping up.
In VRLA, Oxygen evolved at the positive plate is absorbed by the negative plate
without being released to the outside. The negative plates being always in a state of
partial discharge never generate Hydrogen. This completely prevents loss of water.

19. 5. CARRIAGE FAN
400 mm, 300 mm and 200 mm sweep carriage fans are used on Indian Railways
in SG, MOG, and EOG coaches where the system voltage could be DC 110 V or AC 110
V. As a passenger amenity item, carriage fans have to be maintained in such working
condition as to obtain good air flow and trouble-free service for ensuring maximum
passenger satisfaction.
ACCESSORIES
Regulator: The regulator is provided for regulating fan speed in upper class coaches. It
should be ensured that the fan is capable of starting up from rest with the regulator at
the lowest speed step when 85 % of the rated voltage or the lowest voltage of the voltage
range of fan is applied.
Fuse Protection: Tinned copper fuse of 35 SWG is provided as protection for each fan.
This safeguards the fan from surges and short circuit and isolates the circuit in case of
faults in the sub-circuit.
Gimbal ring: This is provided in upper class coaches in swiveling type fans, so that the
passenger can keep the fan angle to any position desired by him for comfort.
DEVELOPMENTS
Developments in this field are :-
1. Use of one ball bearing and one sintered bush bearing instead of both end ball
bearings.
2. Introduction of BLDC fans.
3. Bulk inverters for fans & limited lights for passenger coaches.
Type of Coach No. of Fans
CN (3-tier) 27
GS (2nd
Class-Self Generating) 18
SLR (2nd
Class+Luggage+Brakevan) 9
Chair Car 31
Pantry Car 22

20. 6. CARRIAGE LIGHTING
Carriage lighting is provided from
a. Axle driven generators in conjunction with storage batteries on D.C.110V system.
b. Diesel generator sets with step down transformers on A.C. 110 V in MOG system,
c. Diesel generator sets with step down transformers on A.C.110V in E.O.G system
LIGHTING CIRCUIT
The lighting circuit cable (LC) form the under frame to junction box in the roof is
divided into two circuits through miniature circuit breakers of 35 A capacity for each of
the circuits LI + and L2 +, Circuit LI + feeds the essential lights which fulfill the minimum
lighting requirements in a coach satisfactorily. These include lighting in the lavatories,
gangways, doorways and upto 50% of lights in each compartment /bay, corridor lights
and night lights. Circuit L2 + feeds all the lights other than essential and includes reading
lights in I& II class AC coaches.
In a sleeper coach: -
i) Bar light – 22
ii) Night lamp – 8
iii) Emergency light – 4
iv) Laboratory light – 4
v) Corridor light – 2
vi) Basin light - 2

21. 7. MAINTENANCE SCHEDULES
FORTNIGHTLY SCHEDULE OF MAINTENANCE FOR PRIMARILY
MAINTAINED COACHES:
A) ALTERNATORS:
1. Remove belt and clean alternator externally.
2. Check suspension gear and lubricate.
3. Check safety chains for breakage and availability of split pins in all fixing bolts.
4. Clean the threads of belt tension adjustment gear and lubricate threads, check
availability of split pin in the belt tension rod.
5. Open alternator terminal cover and checkup terminals for overheating and terminal
base for any charring marks. Replace defective terminal boards. Check up for loose
connections and tighten up with box spanner of correct size.
6. Checkup clamp provided for outgoing cables from alternator below alternator terminal
box for proper grip on cables, and to prevent movement on run. Check and ensure
proper fixing of flexible pipes and end fittings.
B) ALTERNATOR REGULATOR:
1. Clean regulator externally.
2. Open terminal cover and checkup terminals for overheating and terminal base for any
charring marks. Replace defective terminal boards.
3. Open regulator front cover and blow out dust with 110V DC electric blower. Checkup
field fuse and replace by correct size. Watch for any visual defects.
4. Secure regulator front cover and terminal cover properly
5. Couple a portable 110 volts DC machine to the alternator pulley castle nut after
removing. the split pin and the belt. Check for output in alternator terminals, regulator
A.C. terminals and D.C. terminals to ensure that generation is alright. In case of no
output D.C. side of regulator, remove regulator and replace by regulator of the correct
type, tested in test bed.
C) AXLE PULLEY:
1. Watch for shifting of axle pulley by observing the white band on either side of pulley.
Position pulley properly, if found shifted and tighten nuts with torque wrench.
2. Check tightness of nut and also availability of check nuts and split pins in all fixing
bolts.

22. D) BATTERY:
1. Clean battery box externally. Remove battery box front door or open the top half
(where the bottom portion is tack welded) and clean the inside portion of front cover.
Check for availability of anti-theft rod. Replace, if deficient.
2. Clean cell top thoroughly.
3. Remove sulphated inter-cell connections. Clean the inter cell connection strip and the
lugs and reconnect by using a fresh fastener. Ensure use of flat and spring washers
for connections. The old fasteners can be taken to the repair shop of the depot,
cleaned thoroughly removing sulphation and kept ready for re-use.
4. Remove end cell connections, clean the connectors and the lugs thoroughly and
reconnect. Replace deficient end cell connectors. If strands are found cut in end cell
connections cut cable near the connector, use an end cell connector and reconnect.
5. Remove vent plugs and checkup ventilating holes for blockage & remove blockages.
Replace non-standard vent plug. Ensure that washers are available for vent plugs.
6. Tap floats and checkup free movement of floats. Watch for worn-out holes in float
guides and replace. Replace defective floats.
7. Check individual voltage and specific gravity of cells with full load 'ON' and record.
Replace broken/defective cells.
8. Check for loose connection in battery fuse terminals and correct size of fuse. Check
for availability of bushes in cable entry holes of battery box and replace, if necessary
9. Watch for low level of electrolyte in cells and top up with pure distilled water only.
10. Apply petroleum jelly on all inter cell and end cell connections.
11. Check tight packing of cells and use additional packing if found necessary.
12. Charge cells, if necessary, at normal rate or boost rate of charge. Record specific
gravity of pilot cells on completion of charge.
13. Enter date of FNE and station in the front cover inner side of battery box.
E) JUNCTION BOX:
1. Open front door. Check all connections in MCB-cum-fuse panel for tightness. Check
availability of terminal lugs for all cables injunction box and provide, if necessary, by
terminal lugs of correct size.
2. Check MCBs for lights, fans and EFTs for correct capacity and proper operation.
Replace defective MCBs. If MCBs are not readily available, provide rewireable fuses
of appropriate ratings purely as a stopgap measure. Checkup negative fuse and
replace, if necessary, by HRC fuse. If rotary switches are provided instead of MCBs,
check for proper operation. Checkup HRC fuses provided with rotary switches for
correct rating and replace, if necessary.
3. Close front door and secure properly by the lock.

23. F) LIGHT FITTINGS:
1. Open fitting with dome key and clean glass dome with a dry clean cloth both inside
and outside. Replace dome if found broken.
2. Checkup lamp holders for loose connections. Checkup lamps for correct wattage.
Replace defective holders and fused lamps. Secure fitting with dome key after
completing the work.
3. In case of side lamps in Guard's compartment, check rotating handle for free
movement and lubricating, if necessary. Clean lens on both sides of tail lamp and red
shield with clean cloth.
4. Clean fixed tail lamp lens.
5. Ensure provision of 15 watts lamps and blue glass domes for all night fittings.
G) FANS:
1. Clean guard and body of fan externally. Open guard mesh and clean fan blades.
Check fan blade fixing screw for tightness.
2. Remove body fixing screws in fixed fans/dust cover in swiveling fans and checkup
carbon brushes for correct grade, length and bedding. Check carbon brush springs
for tension by the feel of hand. Replace defective brushes and springs. Bed the new
brushes before providing in fans.
3. Check commutator for grooving/pitting marks and replace fans if necessary. Clean
dirty commutator with flint paper of zero grade.
4. Checkup fixing bolts of fans for tightness.
5. Checkup connections for tightness in the connectors provided in fan base. Checkup
insulation of flexible leads from the connectors to the fans and replace if necessary
6. In the case of swiveling type fans checkup gimbal's rings for tightness and easy
movement of fans for positioning in the required direction.
7. In first class coaches and inspection carriages check regulator and resistance for
proper control of speed in the different positions. Replace defective regulators and fan
resistances.
8. Replace missing dust covers of swiveling type fans.
9. Check fans for noisy working of bearings, slow working and sluggish starting and
replace defective fans
10. Secure close mesh guard properly after the work is completed.
11. Ensure that fans start immediately on switching ON. A fan which requires a push
start is considered as defective, and should be rectified during FNE.
H) SWITCHES:
Check each switch of lights and fans for proper fixing and operation. Replace defective
switches. Switches should be provided in the locations intended for them and provided
for operation by passengers.

24. I) DISTRIBUTION FUSE BOARDS AND FUSE CUT-OUTS:
Check distribution fuse boards and fuse cut outs for lights and fans for tightness of
connections and provision of correct size of fuses in the fuse terminals. Replace missing
distribution fuse board covers promptly.
J) CALL BELLS IN SALOONS:
Check call bells and indicators for proper operation. Check connections in call bells
pushes and call bells & tighten up if necessary.
K) REFRIGERATORS:
1. Checkup DC contactors for proper operation and clean dirty contacts (in case of DC
refrigerator).
2. Clean refrigerator both internally and externally.
3. Check control fuses and replace overheated fuses.
4. Check compressor belts in case of open type compressor and adjust tension.
5. Checkup functioning of thermostat and proper cooling.
L) EMERGENCY FEED TERMINALS (EFTs):
1. Checkup supply and marking of polarity in EFTs.
2. Replace missing EFTs and those without wiring nuts.
M) GENERAL
1. Checkup earth in coach with test lamp. Trace out fault in case of defect and rectify.
2. Record results of fortnightly examination.
3. Check proper alignment of belt by watching the same on alternator pulley and axle
pulley and correct alignment.
4. After putting on the belt over the alternator, use belt tension gear for tightening of belt
and ensure that the alternator is proper.

26. Requirements of railway coach air conditioning system: -
1. Supplying clean fresh air at a controlled uniform temperature.
2. Catering, within the confines of the Railway carriages to the continuously changing
number of passengers.
3. Providing for heating as well as cooling on a train that travels through areas of widely
differing climate during its journey.
4. Operation of the equipment from power generated, stored and controlled on the train.
Description of power supply: -
SG COACHES
The electrical power for the self-generating type of coaches is derived from the alternator
mounted on bogie transom of the coach and driven by the axle through V belt drive as
long as the coach is in motion at the minimum full load output (MFO) speed of the
alternator. During stationary or when the coach is running at less than MFO speed the
entire coach load is met by the battery of 1100 AH capacity. Two 25KW alternator are
present in RMPU AC Coach.

27. EOG COACHES
The electrical power supply for end on generation type AC coaches is derived from
separate generator cars marshaled at the ends of the train formation, with generation
and transmission voltage of 415 V, 3 ph, AC. The power for individual coaches is tapped
by means of rotary switch from any one of the double feeders running along the coach
leading from the power cars, and coupled between coaches by means of inter-vehicular
couplers. The air conditioning equipment works at 415V, 3 phase AC supply and train
lighting equipment work at 110V, AC, obtained between phase and neutral derived from
a 3 KVA, 415/190V, 4 wire step down transformer.
AC equipment in railway coaches: -
This consists of the following:
1. Evaporator Unit.
2. Compressor.
3. Condenser Unit.
4. Gauge panel.
5. A/C control panel.
6. Air Duct.
7. Refrigerant piping & joints.
8. Wiring.

28. ROOF MOUNTED PACKAGE UNIT (RMPU): -
Two packaged units are used in one coach each mounted above the toilets on
both ends supplying conditioned air into a tapered duct to serve the coach end to end.
The units (two in each coach) are fitted with 4 compressors but operate under normal
with 3 compressors and the 4th one act as standby and works only during peak days of
the summer.
Salient features of Roof-Mounted AC Package Units: -
1. Light in weight, saves fuel for hauling. Total weight of both units is 900 Kg as
compared to 2700 Kg for conventional AC unit.
2. Keeping in view the low price and light weight, the unit pays for itself in one year
Operation.
3. Low cost of installation at the coach building factory since the system is factory
made, assembled, gas charged and tested for performance prior to delivery.
4. The installation requires simply lowering the unit in the false ceiling above the
toilets on both ends of the coach and connection of wiring, drain pipe and flexible
duct.
5. In case of failure, replacement of the unit with new unit can be done in less than
two hours by simply lifting the defective unit by a crane and lowering the new one
in place.
6. The A.C unit remains outside the partition wall and therefore, no chance of water
leakage on passengers
7. Fresh air is taken from the roof through condenser area which gives a relatively
clean air free of the smells of toilets which are common in conventional A.C.
coaches.
8. Hermetically sealed system with no fittings or openings, thus it presents little
potential of gas leakages and break-downs.
9. The unit is almost maintenance free since it uses 3ph AC motors which have no
commutators or brushes to wear out.
10. Uses more environment friendly refrigerant R-22 and very small quantity less than
3 Kg.
11. Mounted on the roof, thus dirt or dust collection in condensers is negligible and
therefore, requires practically no maintenance or water spraying on condenser
coils.
12. No chance of damage due to flash floods during the monsoons.

29. Each compact air conditioning unit (RMPU) has two separate cooling circuits consisting
of the following major components: -
• Two hermetic sealed scroll compressors.
• Two condensers with Cu pipes and pre coated Aluminium fins.
• Two axel fans (condenser fans) with motors for cooling the condensers.
• Two evaporators (cooling units)
• Two twin-sucking radial fans for the supply air (driven by the Evaporator blower
motor)
• Three maintenance covers
• Two air inlets for circulating air
• One air outlet for supply air
• Control and safety devices
• Pipelines/fittings
• Two mixed air filters
Compressors: -
Two hermetic sealed scroll compressors along with Cu pipe lines are provided for two
cooling circuits in each RMPU. They are fixed with anti-vibration mounting pads for
reliable operation.
Condensers and Condenser Fans: -
Two Condensers with Cu tubes and pre coated Aluminium fins are provided for two
cooling circuits in each RMPU. These are air cooled and two axle fan (condenser fans)
along with motors are also provided in each unit for the cooling of the condenser fins.
They are fixed with anti-vibration mounting pads for reliable operation.

30. Evaporators (cooling unit): -
Two evaporators units with Cu pipes and pre coated Aluminium fins are provided for two
cooling circuits in each RMPU.
Supply Air Fan and Blower Motor: -
Two twin-sucking radial fans for the supply air (driven by single Evaporator blower motor)
are also provided in each unit for the supply of cooling air.

31. OBSERVATION
We attended one-month industrial training and internship program in ECoR
CARRIAGE REPAIR WORKSHOP, MANCHESWAR. Here, during our plant visits and
trainings we observed some of the flaws that that we thought can be rectified if bought
under the light. Hence, there are some of the suggestions from our side that we think
can help the company to get more out put in less time. The suggestions are mentioned
below:
• Nickel Cadmium plates can be used in place of Lead plates in batteries
because it gives higher efficiency and longer battery life. It will be a bit costly but
the size of the battery will decrease significantly.
• Sensors should be used in each compartment to turn off the lights and fans in
the absence of people with in that compartment.
• Sensors to be installed in washroom doors for automatic turn on/off of lights while
entering/leaving.
• Solar heaters to be used in factories where hot water is needed.
• Remote operated forklifts to be used in the sheds.
• Waste water to be treated and reused.
• Light tubes to be used in the sheds to increase natural lighting inside it.
• Wi-fi should be installed in coaches.
CONCLUSION
We have completed our training from the Carriage Repair Workshop, East Coast
Railway, Mancheswar. We have observed shops in the Workshop. We mainly performed
our training in the Train Lighting & Air Condition Section.
We got to know about different types of coach, Electrical equipment and wiring
inside the coach, different type of generation system (SG, EOG, HOG), different
equipments in underframe and upper frame section etc.
At last, we have enjoyed learning these new things and we hope we can serve this
nation to the best our knowledge and skills acquired throughout.