Undo and redo don’t work with tiles, as mentioned in the mod’s description, but also not with locomotives and wagons.

Trains are the only thing that you can undo/redo that move, and the way I wrote the mod is largely based on entity positions.
Adding support for it would take a decent bit of restructuring and rewriting, so it might take me a while to get around to it, sorry.
I'll add a note in the description for now though, so thanks for the reminder.

No worries. Hopefully you’ll find a solution. I also noticed that redo doesn’t work properly with regular and chain rail signals.

At least we know that vanilla will have redo functionality built-in in 2.0, which is nice. I still love this mod, though, and hope you find a solution to these issues!