Create: Trains on Trains
If you ever wanted to build a train that carries trains around, this mod is for you. This mod is an extension to the Create mod that makes it so bogeys glued to a carriage but not connected to the track will move along with the train without any problem. So long as the bogeys do not line up with the original ones, you can add as many bogeys to a single carriage as you want!
This mod has been tested with the Create: Steam 'n' Rails mod as well, allowing you to build trains to transport trains with different bogey sizes as well.
This mod is server-side only and does not have to be installed on the client.