There are rails in the game, but a sore lack of any offensive assault trains. It would offer a powerful very mobile gun truck that can bombard enemy forces and cities alike.
There have been various different ways armoured trains have been used. From interwar era experimental/improvised trains with sandbags, armour and machineguns and smaller guns (Estonian independence war) to WW2 era Big Bertha.
I think that train tracks should be one of the easier infrastucture to repair. Not too sure about that, but it does seem easier than roads. Ingame, perhaps railways should have some hitpoints to them. Removing them should be as expensive as building them but they should be able to be sabotaged by some behind enemy lines commando units or shelling and that would generate damage to them and on the hex they'll change to broken rails.
Having a war over a hex where one side builds and the other side removes and other side removes would be silly.