It could be units going to NTC for their annual rotation. I worked on a railhead team when we went in '93 from Ft. Carson. We took Hummvees, 113s, Bradleys, M1As, Duece and a halfs, 5 tons and Hemmits. That was one long train and we had several vehicles go via flatbed truck as well. In fact my dad transported some 113s in '96 or so, with the keys

. Didn't take them off the truck, very tempted to though, but popped the hatch and started one up just for grins.