INTRODUCTION

A passenger train is mainly consisting of Locomotive, AC, NON-AC coaches, Pantry car etc. There is various Electrical equipment i.e. Exhaust fans, coach lighting, vestibule lighting, AC system, water pumps, in the coaches and other equipment's like hot cases, bottle coolers, refrigerators, electric burners, insect killers, water filters, coach lightings, AC system etc. in the pantry car exist. Electrical power is required for running of all these electrical load i.e. hotel load.

The following systems of supply of Electrical power are in use on Indian Railways:

1.Self-Generation (SG)

2.End On Generation (EOG)

3.Head on Generation (HOG)

A.   (SG) Self-Generation: A self-generating coach is equipped with a 25 kW/4.5 kW alternator for generating electrical power. The generated supply is regulated and converted through the RRU (Rectifier-Regulator Unit) into 110 V DC, which is used for battery charging (1100AH/120AH) and feeding lighting and fan circuits. In AC coaches, the 110 V DC supply is further converted into 3-phase AC supply through a 25 kVA inverter for feeding the RMPU (Roof Mounted Package Unit) and operating the air-conditioning system.

B.   LHB (Linke Hoffmann Bosch) Design Coaches: These are being presently manufactured by all production units of Indian Railways. Power supply for these coaches is generated by End On Generation (EOG) or Head on Generation (HOG) system. The LHB variant coaches based on EOG/HOG can be broadly classified.

End on Generation (EOG) System: End on generation (EOG) system envisages providing power car in front and rear end of a rake for coaches for power requirement in between them. These coaches are equipped with 60 kVA step down transformers for stepping down 750 V, 3 AC, 4 wire, 50 Hz supply to 415 V, 3 AC, 4 wire, 50 Hz supply. The 750V supply is fed to entire rake through two feeders running on both sides of coaches along the full length of rake. Power cars at both ends take entire load of whole rake, which includes air conditioning, light and fan circuit, and emergency battery charger circuit and pantry equipment. Each power car has two DG sets, out of which one DG set is standby.

Head on Generation (HOG) System: 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 2 x 622.5 kVA, at nominal voltage of 960 V single-phase, which shall vary with the OHE voltage variations. This 960 Volts single-phase supply is fed to Hotel load converter (capacity 2x500KVA i.e. two units of 500KVA in each loco), which gives 750 Volts 3-phase 50Hz supply as output, for feeding the hotel load of the train.

The system in which power is fed from the electric locomotive to the coaches to cater the hotel load is called HOG system. The supply flow HOG system is as follow: 

C.   Vande Bharat Coaches: Vande Bharat Express (trainset) in India’s first successful attempt of adaption of Trainset technology against conventional system of passenger coaches hauled by separate locomotives. Trainset configuration though complex than conventional train arrangement is faster, easier to maintain, consume less energy, and have greater flexibility in train operation. 

Rake formation of semi high speed trainset consist of 16 coaches with two Driving Trailer Car (DTC) at both end of rake with driver controls, CCMS (Coach Condition Monitoring System) and aerodynamically designed nose cone. 8 motors Car (MC) with traction motors and traction converters, 4 Trailer Cars (TC) with pantograph mounted on the roof and two Non Driving Trailer cars (NDTC).