"I guess from whatever built the train? The best explanation is that they don't think the train exists- which makes the train something they have to stop, right? It's a thing going through dimensions, that they don't think they made."

Which...Sort of makes sense? Maybe not. "We're not really sure why though...but it seems like it might be connected to the homeplanet it was from getting... ...'erased'," he finishes, frowning at the word.

Erased doesn't quite seem right.