Seems so. A locomotive uses a diesel powered engine driving a generator to power the traction (electric) motors at the axles. For years diesel powered subs when snorkeling or surfaced did the same thing. Diesels powering a generator to power an electric motor powering the prop (diesel electric mode). So there must be advantages when powering really big rigs.
Nonetheless I doubt I see such application in even most RV rigs. The addition of a large generator would probably add several thousand pounds. Mine has a GVW rating of about 30000 pounds and sucks petrol like there is no tomorrow. I doubt there would be any net improvement in efficiency—so it must come into play at really big numbers. ??
Nope, there is an increase in efficiency and the generator doesn't have to be that big. Motor either, exact same size as current hybrid vehicles. and that added weight is offset because the engine can be smaller yet produce the same power output to the wheels and the transmission can removed from the drivetrain altogether and the huge one... NO BATTERIES, so the system would be extremely lighter than current hybrids.
I have stating for 30 years that we should have gone to everything Diesel over electric 50 years ago. This is a Dozer but it gives you an idea how the system works and it would have the same advantages even in a much smaller package. Even as small as motorcycles.
https://www.equipmentworld.com/diesel-electric-and-other-hybrid-construction-equipment-are-waging-war-on-wasted-energy/
https://youtu.be/UYBY1k5MhAU