AFAIK many if not most trains (in Europe at least) are diesel-electric.
The drive train is electric, they're just running a diesel generator to power them.
I didn't know, so your comment prompted me to do some reading. Apparently diesel-electric is what has been in use more or less from the start. It's too hard to make clutches usable for trains.
oh, that makes sense. Its been a long time i saw diesel engines and probably thought its a past thing. Apparently not :)
Most freight in the world is diesel (that is diesel electric). For passenger trains, only tourist trains run on non-electric lines - many steam engines, but there are some diesel as well. (Amtrak should take this as an insult)
Most (maybe all?) of metrolink in southern california is not yet electrified or even entirely double tracked. 12m boardings a year before the pandemic so it still gets used.
Another example of a badly run system with success despite itself