Modern Locomotives operate with a diesel-electric drivetrain, for efficiency. Lately, they are making gas-electric hybrid cars.
Why didn’t they build diesel-electric 18 wheelers? I figure, an engine, generator, and an electric motor in each wheel-hub would be moderately more efficient(not to mention far easier to drive)than clutch and who-knows-how-many gears.
This was covered in a VERY recent thread:
http://boards.straightdope.com/sdmb/showthread.php?threadid=63293
Not exactly. Then other thread touched on the subject, but I don’t see a conclusive reason why trucks are not diesel-electric.
(My guess would be either overall weight or else that the diesel-electrics would have a hard time on steep inclines.)
I know the Army asked the U.S. automakers to try a diesel-electric system on the standard 2 1/2 ton 6×6 around 1970 and it was shown to be not effective (using 1970 technology and costs).
The huge dump trucks used in open pit mining (the ones where a baskeball player has to look up to see the wheel hub) are diesel-electric, but you’ll note that the grades inside a pit mine are never steep.
As are the giant front-end loaders, etc. They’re made right here in my town! 
Each wheel has its own motor (the whole wheel motor thing was invented by Mr. LeTourneau, who then founded the manufacturing company and the college here).
Quite right. I was engaging in the kind of anal whinging and pulling apart of other people’s threads of which I am so often critical myself. Apologies. :rolleyes:
Actually I asked this question in that thread and didn’t get an answer, perhaps I should have started a new thread. TheLoadedDog --The SDMB CoPs are going to have to come confiscate your flashing light and utility belt ;).
I have been thinking about the OP for a few days now and have come up with a few WAGs.
Not much opportunity for regenerative braking since trucks travel at a constant speed for long periods of time, but this applies to trains also.
A train has a very low power to wait ratio (I think), acceleration is not really an issue. Perhaps this system is most efficient for vehicles with a very low power to weight ratio and/or operate at very low speeds for an extended periods of time.
Ten speeds in most trucks, but you are shifting into seventh at 30 MPH.