User blog comment:Rose Hunter/The Old Lady's Identity?/@comment-26890640-20151104070927

Hmm I'm going to have to do a bit more searching around for a suitable tale, but what if the old woman was a usurped  "Evil (Witch) Queen" archetype? She lost her kingdom and had an awful life thanks to her previous role. She'd maybe be a bit more of a tragic character in that case I suppose. She would be afraid of being forgotten so has resolved to creating a bitter vengeance, targeting destinied students with a special hatred for those in hero roles. As the journey goes on, the locations become more and more relevant to this woman's story and go in the direction of her kingdom. At this point the train would be locked down with her powerful magic (she isn't very skilled at magic but has been practicing restraining and trapping spells for years just for this moment) so no one can exit. She aims for a hostage situation with a prince or princess she could use for levarage because of a misguided idea that she could become a queen again through holding them ransom. You see, at the end of the journey, she's destroyed a bridge over a canyon...

The time limit for her demands is the train ride, the students are merely leverage for her plan but she'll still torment them while she's at it.