This is probably the most current roster available online:
http://military.railfan.net/roster/" onclick="window.open(this.href);return false;
It hasn't been updated for a while, so it's not 100% accurate. For example:
The 1205th TROB, a USAR unit, was inactivated on 30 Sep 06 and its two locomotives, USA 4601 and 4602, went to the TVA.
Hill AFB, UT, closed its base utility railway a couple of years ago. The Army rail shop, a tenant activity, is still present, however.
MCLB Albany, GA, put its two GE 80-tons up for sale, although the base may still receive some limited rail service from the connecting carrier.
MCB Camp Lejeune no longer has its own locomotive, and the one listed on the website went to a tourist railroad some years ago. NS still serves the base.
MCB Camp Pendleton's tiny amount of track no longer has a locomotive.
The track from the CSX interchange to the base at Indian Head Division, Naval Surface Warfare Center, MD, was lifted in about five years ago and the route is now a paved, county-owned trail. The GE 80-ton was trucked to a buyer in Nevada and the ex-Army SW8 was bought by a dealer that moved it to the power plant at Chalk Point, MD.
The rail operation at NWS Seal Beach, CA, has closed.
Although the online roster lists two GE 80-tons at NWS Earle, only one is present, and it is inoperative. The other has been gone since some time in the 1990s.
There have been some roster changes at other bases as well.