Railway Reforms

Head on Generation (HOG) technology


From UPSC perspective, the following things are important :

Prelims level : HOG technology

Mains level : Making railways function affordable

  • The Railway Ministry has announced that it would be upgrading all existing Linke Hofmann Busch (LHB) coaches with the Head on Generation (HOG) technology, a move that would cause the trains to become more cost-efficient and less polluting.

LHB coaches

  • The LHB coaches have been built in India at the Asansol-based Chittaranjan Locomotive Works (CLW) after the Railways purchased their technology from the German manufacturer Linke Hofmann Busch in 1996.
  • These coaches were originally designed to operate on the End on Generation (EOG) principle.
  • According to a research the train’s ‘hotel load’ (the load of air conditioning, lights, fans, and pantry, etc.) is provided with electricity from two large diesel generator sets, which supply 3-phase power at 750 Volts 50 Hz to the entire length of the train.
  • Each coach then picks up the power supply through a 60 KVA transformer, bringing down the voltage to 110 volts at which level the equipment in the compartment is run.
  • The generator cars are attached to either end of the train, giving the system its name.

Head on Generation (HOG) system

  • As opposed to the older EOG system, the Head on Generation (HOG) system runs the hotel load by drawing electricity from the overhead electric lines through the pantograph (an apparatus which mounted on the roof of electric train to collect power through with an overhead tension wire).
  • The power supply from the overhead cable is 750 volts at single-phase, and a transformer with a winding of 945 kVA converts it to a 750 Volts 50 Hz output at 3-phase.
  • This energy is then provided to the compartments.
  • The HOG system is free of air and noise pollution.
  • The system would bring down yearly CO2 and NOx emissions, which according to the press release are currently at 1724.6 tonnes/annum and 7.48 tonnes/annum respectively, to zero.

Why HOG?

  • Since the HOG-fitted trains do not require power from diesel generators at all, they only have one emergency generator car attached, instead of two regular generator cars.
  • The Railways has said that the extra space created would now be used for an LSLRD (LHB Second Luggage, Guard & Divyaang Compartment) meaning more passengers can be accommodated.
  • Once all LHB trains get the new system, the Ministry said that it would be saving INR 1390 crores every year.
  • The increased cost efficiency is because of the low price per unit of electricity in the HOG system @ INR 6/unit, as compared to the price of INR 22/unit in the EOG system.
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