[supercat]

Yes. OTOH there could be something to be said for a hybrid diesel.

Diesel locomotives are all hybrids.

That having been said, there is a very important difference between locomotive and automotive design objectives.

Locomotives are supposed to be heavy. Even if one were to produce a miraculous power source for a locomotive which could supply all the needed power and energy in a fifty pound package, one would still have to throw in many tons of balast to have a usable locomotive. By contrast, cars are supposed to be lightweight. If someone could design a car's power source to be 50lbs while still providing useful power and energy, that would be a major engineering coup.

[conservatism_IS_compassion]

Even if one were to produce a miraculous power source for a locomotive which could supply all the needed power and energy in a fifty pound package, one would still have to throw in many tons of balast to have a usable locomotive. By contrast, cars are supposed to be lightweight. If someone could design a car's power source to be 50lbs while still providing useful power and energy, that would be a major engineering coup.

All true. But at least so far as fuel economy is concerned, the energy recovery/storage of the hybrid is of course intended to ameliorate the energy loss otherwise associated with braking of a massive vehicle.

Diesel locomotives are all hybrids.

They are if in fact they include large batteries - a fact of which I have not heretofore been aware ( gogeo could be right, I suppose . . .).

[AmericaUnite]

I don't know much about a car's engine. But, I can't stand the smell behind a diesel car even if it's a Mercedes.

It's like being behind a bus.