Also it hasn't added spline points, so deleting the offending section will delete half the station, and part of a random hedge somewhere...
I'm thinking the correct course of action is just "Restore from backup, swear a lot, and rebuild any changes since I backed it up", but I'd like to know what in the name of sanity actually happened, if only to stop it doing that again. Possibly of note, when I went to open it, it was marked faulty, and after clicking "view errors", it thought about it for about 5 minutes before spitting out
umm, Wut??Error: The Tag 'thumbnails' is not permitted within a container of type 'map'.
Opening for edit and committing again cleared that, but then it opened up to the mess as described above.
Sometimes I wonder why I bother, since half the time I make changes to a route, Trainz has an aneurysm and I'm forced to recover from a backup...