Snowmelt ,springs and sheep.

I drank plenty of times from the pipe coming form the cisterns at Sublette and Cumbres....great, sweet water. I did that till Fritz Bauer pointed out that if you opened the cisterns you could spot one or two skeletal creatures at the bottom! Trackside springs were the safest to drink form,and there were quite a few along the narrow gauge lines. The section men knew where the best ones were. I contracted giardia (yep, from drinking from a crystal-clear mountain stream).It recurred periodically for many years. Sheep poop is the main culprit.

The D&SNG issued water bags for years. We would hang them in a handy place, like the flag holder. Bradshaw hated this (because it scratched his precious paint),so the r.r quit issuing them to the crews. Desert bags are still available from Coleman. We would shoot some water on them periodically and they would stay cool. After I was promoted to engineer I didn't need as much water so I would carry it in a bottle. Before long nobody was using the bags any mpore. Some of the younger D&SNG crewmen are taking the Desert bags with them again. One thoughtful soul hung one on the 315 when we went to Silverton with it.