My personal winner for this jam. The puzzle mechanic is very complex and multi-variable, but still comprehensible to feel like solving as opposed to guesswork. Solving these were a blast, and especially 'The Great Migration' really stumped me.
I think the only thing I could think to criticize would be the visuals at some (very minor) points. Sometimes if a train was moving on a track that was about to change direction, it would teleport unnaturally to the correct spot. Also, I think the brown void surrounding the puzzle could use some detail. However, I recognize that for a game jam neither of those are real priorities, and I mostly say them out of necessity to find something to improve upon.
Incredibly well done. Your #1 in gameplay and #2 in fun is absolutely deserved.