I'm pretty sure that all (or as near to all as to make no difference) modern trains use electric motors, at least in the developed world, but, AFAIK, only local commuter-type trains are actually electric. The freight and long-haul locomotives are predominantly (exclusively?) diesel-electric hybrids--the traction motors are electric, but they carry diesel engines to generate the electricity.
They've actually been in use for around a century; the WWII Balao-class subs used basically the same powerplants as the diesel-electric locomotives of the day. There was actually consternation in the Silent Service early in the war because they were stuck with an inferior powerplant because the FM units were allocated for (or at least going to) locomotives.
Oops! I did my post before I read the entire thread. Oh well. Like minds and all that!
Woody