I mean, I do sell a Riding the Rails conversion with maps.....just sayin' (note, I am not here to shill, but my wife chastised me the other day for not doing so). (also, I have some thoughts here: https://mikesixel.com/riding-the-rails-learnings-and-update/ )Fair enough! I haven't done a lightning rail adventure since that one, so it might be time to throw in another one. (That is to say, the PCs have ridden the lightning rail a few times since, but it's just been an uneventful way to get from A to B.)
Actually, I think any good city adventures is what I'm looking for......

Riding the Rails 5e Conversion - Dungeon Masters Guild | Dungeon Masters Guild
Riding the Rails 5e Conversion - edit: NOTE: I recently posted thoughts on how this will be updated here: https://mikesixel.com/riding-the-rails-learning