হাওড়া - বর্দ্ধমান কর্ড লাইনে যান, 130 কিমি বেগে ট্রেন যাওয়াও কালবৈশাখী ঝড়ের থেকে ভয়ঙ্কর! - Jishnu Thakur

Indian railways have introduced the head on generation (HOG) system in the New Delhi – Mumbai Rajdhani Express train to save Rs.5.5 crore in power costs annually. The technology has been introduced on a long-haul train for the first time in India. Presently, the Rajdhani and Shatabdi trains run on end on generation (EoG) system in which train coaches receive power from diesel-fueled power cars for lighting and air-conditioning. HoG is a clean technology that taps power supply overhead power lines and distributes it to train coaches for lighting & air-conditioning.
The other advantages of HoG system over EoG system are:
HoG...
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system does not create noise pollution. Power cars generate noise of 105 dB.
It is environment friendly technology as power is drawn from overhead power lines instead of diesel generators.
so its approximately this much ..
need more time for more info :-)