For you info,

North American transportation requires that the Rail car and load be inside what is called AAR Plate C  clearance diagram,
which is basically 15'6" high above rail height.  Subtract the height of a rail car,~ 4' and you have your allowance.

In Europe you have to be inside the UIC clearance diagram which is much more complicated and basically 14' 1/4" high.

Hope this helps,  Steve Cotsford