[ceejayoz]

That might be balanced somewhat by not needing to maintain thousands of miles of caternary wire.

[echoangle]

I think maintaining thousands of miles of wire and one large powerplant would be cheaper than maintaining thousands of small mobile reactors, but that's just speculation of course. And most of the wire has to already be there anyways for passenger transport, I think, because many rail lines are used by cargo and people. Unless every train should have a reactor?

[lukan]

Once we have cheap miniaturized fusion reactors, that work stable - we won't need so much electric wiring anymore, true.

Unfortunately, so far exactly 0 working fusion reactors have been build, so currently, I would not demolish electric lines just yet.

[kjs3]

The underlying technology does not exist in a production form, to the extent that it's not clear which basic reactor design option is going to be the future. So we can't know what the maintenance burden from a fisson rector is, much less one mounted on a train. Don't plan on tearing down those overhead cables just yet.