I think that's what parent meant. Doubtful. Electric in EMU or in the context of Caltrain electrifying means pure electric traction power. In the United King

I think that's what parent meant. Doubtful. Electric in EMU or in the context of Caltrain electrifying means pure electric traction power. In the United Kingdom I think they make some differentiation between a DMU (diesel-hydraulic, like an automobile with an automatic transmission) and DEMU (diesel-electric like a locomotive). There were diesel-hydraulic locomotives along the west mainline for a bit, but in general diesel-hydraulic locomotives were fairly uncommon. If it's being called electric it's not going to have a diesel engine of any sort.