what is power car or generator car.

A "power car" and a "generator car" are essentially the same thing, referring to a railway carriage equipped with a diesel generator to provide electricity to the rest of the train, powering features like lighting, air conditioning, and other onboard systems; in simpler terms, it's a dedicated car that generates power for the entire train, usually positioned at the front or end of the train. 

Key points about power/generator cars:

1.Function: Their primary role is to supply electricity to the train's passenger coaches through a system called "end-on generation (EOG)" where power is distributed from the power car to each coach. 

2.Power source: Most commonly, they use diesel generators to produce electricity. 

3.A power car also uses Head on Generation (HOG) technology. HOG technology is a clean energy system that uses power from overhead lines instead of diesel generators.