Towing a train with another train is technically possible (there are tow bars designed specifically for that), however I was told by the Shop manager that that option, after 2009, is basically the absolute worst-case scenario and probably wouldn't be done. A parking tram cab is capable of pulling the monorail, and they've tested that option so I would assume if this train couldn't be powered up, they would try that first.
However, what I assume was the case is that maintenance was/is able to fix the issue and restore power to the train, but they knew it would take a long time, and Ops wanted the Guests out of the hot train before that point, so they evacuated it rather than wait. Once power is/was restored, a pilot would be put into the cab with a cherry picker (jealous) and move the train off the switch and to a station.