A diesel-electric transmission system includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors. No clutch is required. It also is able to supply full torque at 0 RPM. Diesel-electric systems are also used in submarines and surface ships and some land vehicles.
I was always fascinated by locomotive engines, particularly due to the engine and drive train combination. The statement above regarding full torque at 0 RPM is rather thought provoking if you've never looked at these systems. Imagine solving how to couple a mechanical transmission to thousands of ft-lbs of torque and the problem becomes very interesting which is why the decoupling is pretty cool. Yes, yes, there are mechanical transmission locomotives, but they are generally for light work comparatively.
A diesel-electric transmission system includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors. No clutch is required. It also is able to supply full torque at 0 RPM. Diesel-electric systems are also used in submarines and surface ships and some land vehicles.
https://en.wikipedia.org/wiki/Diesel-electric_transmission