So far I always neeeded military control of a region, before I can transport anything by rail. I wonder if this is not somewhat unrealistic, as it precludes the railway war that was in fact a very essential part of this Civil War.
For example the german General von Hoffmann wrote: "It is the most comical war I have ever known" "We put a handful of infantrymen with machine guns and one gun onto a train and rush them off to the next station. They take it make prisoners of the Bolsheviks, pick up some more troops, and so on."
The Socialists also conducted railway war during 1917, that was how they could take control of the country so quickly.
I know of course that it is a very improtant feature to balance the game. Perhaps railways transport in uncontrolled regions could be restricted to just certain, very small units?