They could make a lot of interesting ideas! Especially on the 1939 map…
I’d say Artillery, AA guns and infrantry can move 1 extra space.
Rail markers and rail station markers work the same way except units can only hop off and on trains on territorries with rail station markers.
They can only move through territorries adjacent to territorries with rail station markers or rail markers.
They can not move on trains when their move ends on a territorry with only a rail marker. So you would always have something like this Rail station -> rail way -> rail station -> rail way -> rail station etc.
They can be SBR’d up to 6 dmg points (like AB’s and NB’s).
they would cost… I don’t know… Rail stations slightly more then rail ways. I’d say 6 and 9 (wich equals the 15 of a NB or AB) and give every capital or territory that starts with a major industry complex a rail way station marker and some territory in one of the most eastern soviet territorries as well… No rail ways yet.
Maybe something like this?
Or maybe make them cheaper… railways were fairly cheap to build… I’d like to see how it would balance things out tho… And I wonder how many at the same could move faster… Maybe 4 units at a time (at least 2 infrantry)?