I don't see why trains need to be remaked for OC in the first place. While trains with tracks sound like a fun idea, they resulted to be a unhelpful from the beginning. Most reasons were written by Nachtschatten just now. I can think of many other possibilites for stuff that helps with explorating and developing ("erschließen") terrain, making transport of materials easier.
One thing that just came to my mind is a sling-shot with an opening like e.g. the foundry that catapultates the thrown in material automatically to a given location (e.g. another slingshot etc). I am sure we can think of many other possibilities, perhaps based on the new control with the mouse.

Why does it have to be a train?
Or better question:
Why first think of the object and then think of how we make it (come hell or high water) useful?

Edit:
My intention is not to spoil a possibly fruitful discussion. I can think of scenarios where it might be really cool and fun to have to build a train route from one end to the other (as the goal). I basically want to underline that the "Ich will ein Kran!" (I want a crane) perspective of designing a playable object pack is the wrong end to start a design process.