Blast it all! The track behind the tree, in a place hard to reach, has come apart.
Remedy: Rubber bands. Yep, take rubber bands – the stronger the better – and, after the track sections are in place, wrap them across two ties back from the track joint and connecting to the ties under the other side of the track joint. Yes, success! Now, chances of separation is greatly reduced. Sure, the LGB and Aristo tie-connector strips can work. Don’t have 'em you say. Got rubber bands?
Merry Christmas!
Wendell