Diesel electrics can be big enough and with long enough expected lifetimes to go 'all out', I think in some ways they can get closer to CCGT as far as efficienc

Diesel electrics can be big enough and with long enough expected lifetimes to go 'all out', I think in some ways they can get closer to CCGT as far as efficiency. Where the challenge comes for smaller vehicles, is the more power you are trying to give, the more you have to build everything up; not just the engine but whatever that engine is inputting into, also trains have somewhat more predictable speed profiles over a trip vs a car. This is why some manufacturers have vehicles that are PHEVS but really BEVs with an 'oh crap' extender that can struggle to keep up a good grade. I gotta give TRD/Toyota/Ford credit, the HSD style drive train does work around a lot of this stuff for PHEVS; in lockup mode you have a 1:1 ratio with minimal losses and at that point it's up to the ability of the engine to adjust profile. Works very well in practice, and far simpler than the setups of others.