The document discusses different train lighting systems used in Indian Railways. Self-generation (SG) systems involve axle-driven generators and batteries in each coach, while end-on generation (EOG) uses diesel alternator sets in power cars to provide centralized power. Head-on generation (HOG) receives power from the locomotive. EOG and HOG are more reliable and efficient than SG. HOG is cheaper than EOG but still requires a power car. Overall the document provides an overview of the technical aspects and tradeoffs of different train lighting power supply systems.

1. TRAIN LIGHTING
SYSTEM

2. INTRODUCTION
 Train lighting is one of the important passenger amenities
which influence the image of Railways.
 First train ran on 16th April 1853, train lighting system came
to Indian Railway in 1930 through axle driven Dynamo.
 Power supply system for trains is designed and developed to
suit the requirement of AC and non-AC working in the trains.
 Few factors considered for development of such
systems are as under.
• Coach load
• Speed of the train
• Weight of the equipment
• Available technology for reliable equipment etc

3. TYPES OF GENERATION
 Self-generating
• Axle driven system working on 24V DC/ 110 V DC
 Mid-on-generation
• MOG with 415V, 3 phase generation, and 110V AC utilization
 End-on-generation
• EOG with 415V,3 phase generation, and 110V AC utilization
• EOG with 750V, 3 phase generation and 415 & 110V AC
utilization

4. TYPES OF GENERATION
 Head-on-generation
• Power feeding from OHE for lighting loads (EMUS):
 750V DC –light & fan works on 110V DC
 1500V DC – light & fan works on 110 V AC
 25 KV—light & fan works on 141 V AC
• Power feeding from HOG for Hotel Loads (Loco):
 Hotel load power is taken from Electric/Diesel Locomotive.
 Hotel load power supply taken directly from OHE through a separate
pantograph mounted on the power car.

5. SELF GENERATION SYSTEM:
 The power supply arrangement of SG coach has under slung
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
110 V DC and is used for charging the battery. The electrical load of
the coach is supplied through the 110 v DC battery at the halt.
 Advantages:
• The system is independent of the mode of traction.
• As each coach has a battery, so no additional source is required.
• The problem/defect in any particular coach does not affect the
others.
• The system can be designed to suit its specific requirement.
• It gives better flexibility in rake formation majority of SG type
coach is more.

6. SELF GENERATION SYSTEM:
 Disadvantages:
• The electrical load of the coach is restricted by the limitation of the capacity of
generation i.e. 2*25 kW per coach at present.
• The power is not generated during standing or slow movement of the train,
therefore bulky batteries are provided.
• There is no standby source for alternator and batteries, so system became poor
reliability.
• The system requires the extensive maintenance of alternator, batteries, belts,
tensioning device etc.
• The system has the very poor efficiency of 57%for power it receives from the
locomotive.

7. SELF GENERATION SYSTEM:
BASIC CIRCUIT DIAGRAM

8. END ON GENERATION SYSTEM:
 Each EOG train has 2 power cars with 2 nos. of DA sets in 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,415 V 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 24 V
battery is used for supplying a few emergency lights provided in
the coach.
 Advantages:
• The system does not require the use of bulky batteries and alternators in
individual coaches.
• The system has higher reliability due to standby DA sets and reduced
number of equipment.
• Due to an elimination of heavy equipment, the dead weight of the coach
is reduced.
• The system is independent of the type of traction i.e. diesel or electric
locomotive.
• The system has better energy efficiency as compared to the self-
generating system.
• Low maintenance.

9. END ON GENERATION SYSTEM:
 Disadvantages:
• The cost of energy is high due to fuel cost.
• Even with 750V, 3 phase, there is still an effect of voltage drop at the farthest
end of the train.
• Noise and smoke pollution are generated from power cars.

10. MID ON GENERATION SYSTEM:
 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 415/110 V. The
110 V AC supplied to the coaches through couplers. The system
was discontinued after the introduction of EMU and DMU service.
 Advantages:
• The system was most suitable for slow-moving branch line passenger
trains. Light and fan of all the coaches had centralized control in power
car coach. Fan and lights were working on AC supply. There was no need
for standby batteries in the coaches.
 Disadvantages:
• There were noise and smoke; pollution due to DA set working.
• The operator was required to power car coach.
• Some valuable passenger spaces were occupied by DA sets.

11. HEAD ON GENERATION SYSTEM:
 The HOG scheme is widely used power supply by Railways world
over.
 The power supply system for the coaches is either received from the
locomotive or it is directly tapped from traction overhead lines into
the power cars.
 The system is considered to provide cost-effective, reliable and
energy efficient supply system for coaches.
 The HOG scheme can be considered with following two options.
 Hotel load power is taken from Electric/Diesel Locomotive.
 Hotel load power supply taken directly from OHE through a separate
pantograph mounted on the power car.
The second system is not considered technically feasible for
Indian Railways due to some limitations.

12. HEAD ON GENERATION SYSTEM:
 The power supply is received directly from locomotive through
couplers. The supply from locomotive can be a 750v, 3 phase supply
or a single phase supply received from loco is regulated and stepped
down in individual AC coaches, with the help of converters to provide
a regulated 415 V, 3 phase supply.
 Similarly, in AC coaches, power supply from locomotive can be
stepped down and regulated to provide single phase, 110 V AC
supplies.
 One power car with standby DA sets is also used in the train, which
can supply power to the coaches in case of failure of a locomotive.

13. HEAD ON GENERATION SYSTEM:

14. HEAD ON GENERATION SYSTEM:
 Advantage:
• Cheaper cost of power as compared to EOG & SG system.
• Pollution is less as compared to EOG system.
• One power car may be replaced by trailer coach, revenue increased.
• Escorting staff will be reduced to one power car.
• The net dead weight of the train is reduced as compared to SG system.
• HOG type AC coaches can be used in EOG type trains.
• This system is compatible with diesel and electric traction.
• Maintenance cost of HOG system coaches is lower as compared to SG
coaches
 Disadvantages:
• While working with electric locomotive there are power interruptions for short
durations to various electrical equipment except for lights while through the
neutral section.
• One power car is still required for supplying power during failure of OHE
supply or locomotive etc.HOG type coaches require rake integrity of coaches
similar to EOG system.