Inspired by the true intent of the Battle Environments post by the coeurl masta.

I want to open the floor to a Train themed mission/instance/raid suggestions.

An environment that gives the impression we are moving at high speeds through the land (and thus making a time limit to resolve more relevant)?

Fighting against Imperial soldiers, transported monsters that break free, etc. A difficult checkpoint fight such as a Magitek war machine?
Steals a ball of yarn from Antanias before he gives it. Hidden message bonus +1.
Objectives from separating a VIP rail car, switching the rails to change destination - affecting the encounters ahead (normal mode, hard mode), preventing a "phantom" from taking over the train, to fighting enemies or "an enemy" on an adjacent train toward the end.

Just throwing it out there to take advantage of the Battle Environments forum where the topic may stay on the first page for weeks over say... General Discussion where a topic will get far more attention, but become harder to find a few days later.