Better near Toronto...

There's a place in St. Jacob's that has some train car's that aren't quite abandoned, but some are pretty far into disrepair (although others look fully restored). I'm pretty sure they're owned, along with some coal locomotives by a local rail club. There's also a pretty cool train bridge right by them, as well as tracks that have some pretty cool views if you walk along them for a few miles. So although I wouldn't say it's worth the trip if you're very far, it is pretty cool to spend a few hours looking around if you're already nearby.

Halton County Radial Railway in Milton.
http://www.hcry.org/

I'm not that far! Will have to check this out.