Thanks for the report, fixed in the latest version
I guess the list can not be assigned to the train anymore. Trains now have a unique ID since version 0.15.11 https://forums.factorio.com/viewtopic.php?t=46234
Maybe is worth to change it?
It actually was the empty schedule. In 0.14 an empty schedule would have shown up as a table in lua, now it's just nil.
Train.id will be made use of soon(ish), it's just a rather big change, since i want to use it in FARL and FatController as well.