diesel, electric, or diesel-electric

Have you ridden on a diesel-electric train before? The Malaysian KTM trains are pulled by diesel-electric locomotives, and I believe the SMRT maintenance vehicle that broke down yesterday also runs on diesel-electric.

What is diesel-electric? Basically you feed it with diesel to run the diesel generator, which produces electrical power that in turn runs the electric motors, which turn the wheels. From mechanical to electrical and back to mechanical, you must be wondering why not use a direct drive system and directly turn the wheels with the diesel engine?

Unlike a car which normally only has to power 2 wheels, a locomotive has so many axles it will require some really messy gear box for transmission if we are to use direct drive system. And we haven't talked about maintenance.

This sounds like eating vegetable that you fertilised using your own crap.