Interesting.
I've seen the opposite extreme of a firefighting train, on the 762mm gauge Kiso Forest Railway in Japan. That one consisted of a motley collection of water tanks about the size of home heating oil tanks, no two alike, mounted on old wood-frame disconnect trucks about the size of warehouse flatbeds. The bigger car with the diesel pump and monitors ran on two disconnect trucks. Since the railroad was (at that time) the only access to a huge forest, that train saw a fair amount of use.
The Rintetsu closed down in 1975. A look at a modern map shows the area laced with paved roads - and a satellite view shows even more unpaved logging roads. The rails were done in by self-loading trucks.
Chuck (Modeling Central Japan in September, 1964 - including a 762mm gauge fire train)
While looking at my FB site I found the following link from Friends of the BNSF site: referencing 'a new Firefighting train' to be based out of Spokane, Washington area.
Link @ http://bit.ly/14446pr ( Friends of the BNSF site)
The site shows photos of the construction of the Firefighting car ( made from a bulkhead style flat car) It also has a couple of links that show the finished car and a tank car and the accompanying BNSF Extended View Caboose assigned to the train.