Apache powder had an network of 3 foot gauge track at their dynamite works near Benson , in Southeastern Arizona . The had a dozen Porter 0-4-0s that were fireless cookers .The rail system lasted till the early 1970s .Two of the engines are on display at the dynamite works gate and in Benson . Entry in the dynamite works is strictly forbidden ,but a railroader who switches in the works said there is still a lot of narrow gauge track in the property .He also saide that some of the warehouses are so full of crystallized nitro in the walls and floor that they are off limits to ALL employees !