Your ideas for fire suppression seem very sound in basis but I believe there are a few operating considerations that whould have to be checked out with Gerald:
1. Backing the passenger train down grade.
2. Delaying the passengers.
3. Placing the passengers and train in the middle of a fire scene.
The rotary tender already has plumbing for a gravity flow sprinkler system which has been used before. This wets down the right-of-way and takes care of a lot of fires. The speeder crew with bladder bags and hand tools take care of most of the rest. We also have a new fire attack truck from the forest service which would be manned by the shop and/or track crews. If past years are any indications then the train also will probably be bird dogged by firefighters from the forest service. Maybe your idea of a tank, pump, and attack lines could be down-sized to fit on a speeder trailer. Wouldn't be a lot of water, but would be a great aid to the speeder crew. Again Gerald would be the one to discuss this with.
With a second engine up and a third next week it looks like the problem of displacing passengers for fire suppression efforts won't happen. Geof Gordon told me a week or so ago that the RR would double head out of Chama if the passenger load demanded it. Looks like this could happen right from the git-go.