How to traine follow rails?

I need to make a traine that follow the rail system.

The quastion is from what i should start? NavMesh or object tag aligment or?Maybe somebody now the shortest way for that? Thanks Sorry for bad English.

I seen a lot of questions about trains on this list that use iTween to move along a path. The best solutions typically use iTween.PutOnPath() and iTween.PointOnPath() rather than use the iTween specific movement functions. There are often issues with keeping the cars connected (visually) as they move around the track (especially on tight turns), but I think you will have this problem with any non-physics, moving-on-path solution unless you add specialized code.

You can get iTween free from the Asset Store.