I was on the final loop the train ran before it shut down. All of the train cast members were riding. Talking with one of them, she said that there was a lot more work other than just TRON that was going to happen, and that the trains would be down for much longer than anyone expects. Apparently, there were some other track repairs that needed to be done, scenes that needed updating or repairs, and other maintenance items that they couldn't do while operating the trains. I didn't get specifics outside of what is listed above.
-Spot