First of all, Welcome to the Forum.. My information is not current, but some years back there was a large railroad operational set up at Fort Eustis, Virginia... I was told that that was the HQ for all Army train (Transportation) training and operations. And a Public Museum at the gate.
Here are a couple of web sites that might be helpful:
http://en.wikipedia.org/wiki/Fort_Eustis
http://www.transchool.eustis.army.mil/
This one particularly might be a help! :
http://www.globalsecurity.org/military/agency/army/1205trans.htm
Good Luck, Hope this helps!