Trains were used to bring supplies into camp, and they also brought up temporary housing. They looked like railroad cars converted to housing, but were smaller. In one of the photos an engine was off the track. Possibly the rails spread from the rains and heavy mud, or just got top heavy with the load. The men got the horse teams out and managed to pull the train back up onto the tracks. Amazing what a few men and a few horses can accomplish. Without cranes!
Time to sleep. Will try to get more up soon.