Diesel Trains

[Tobyman]

Can somebody tell me the difference between diesel electric and diesel hydraulic locomotives and how they work.

[sddsddean]

Both have a diesel engine. In a diesel electric the engine drives an alternator/dynamo which provides electricity to power the electric motors on the axles. In a diesel hydraulic, the engine powers a hydraulic pump in the hydraulic system which provides power to the hydraulic motors on the axle.