Thanks for posting these photos of the Davenport at Fort Benning - really interesting.
I saw the restored US Army Baldwin at Taco des Lacs in France last year. Patrick did a terrific job restoring her (it had ended its days in Australia as an 0-6-2T, rather than a 2-6-2T as built) - he used "Narrow Gauge to NoMan's Land" has his main referrence text during the re-building to original condition!
The US entered WW1 quite late in the conflict, initially they were using a lot of British & French Equipment (plus captured German vehicles). After a while thier own equipment started to be delivered in bulk. The main vehicles the US had in use in France were 35 & 50hp Baldwin gas-mechanicals, Baldwin 2-6-2T steam locos & a lot of "Pershing" Boxcars, flat/stake cars, gondolas and tank cars.
Just as manufacturers had ramped up production, the war ended. A lot of equipment - steam locos (from Davenport, Vulcan, Baldwin - all 2-6-2T to the same general design), tractors, rollingstock never got shipped to France/Europe & instead remained at various US Military bases.
The "Caboose" that is shown in the photos, is something that seems to built by the army on a standard "Pershing" underframe. I have 2 sets of these underframes in the UK at the moment that I am about to restore - one as a Flat car, the other as a gondola.
The museum that I am involved with is planning a major event in September 2014 - to mark 100 years since the start of WW1. We are specifically celebrating these light railways used by all sides.
I got my books today... Narrow Gauge to No Man's Land and Two Foot Rails to The Front. I'm just as fired up about this modeling subject as I was when I started this thread. I can tell before its all done I'm going to have to learn how to build my own engines because I have to have one of those Baldwin gas mechanical locos. In the mean time, some of the other more simple locos are going to get built.