Don't know about that. CSX uses them and their competitors quite a bit.
These guys are amazing to watch, though. Basically, the railroad guys get the heck out the way, and these crews start dragging stuff around -- eventually getting everything either cleared from the track or re-railed.
The tracked machines are called sidewinders. They move an awesome amount of equipment when they gang up on it as shown in the picture -- with one on each corner for a large locomotive unit. They just keep working at it until the work is done - zipping around barely missing each other -- then they leave.
Hint: it's not inexpensive, this service.