Bridge platform and barrel Question? - Model Railroader Magazine

The barrels on little extended platforms (actually supported on switch ties which replaced three of five standard ties) were water barrels, and were usually found on wooden trestles.  They were supposed to be available in case of fire, so the local section hand would have something at hand to extinguish smoldering spots - preferably before the entire trestle was fully involved.

I don't know how useful they would be on a steel bridge - but, then again, their real value on a trestle depended on the presence of a trackwalker in the immediate vicinity who could respond to the first wisp of smoke.  I DO know that the New York rapid transit line I used every day in high school (and the others I rode in my spare time) had miles of wooden-decked steel girder elevated structures with nary a water barrel to be seen.  (Of course, the railroads couldn't call on the NYFD to put out a trestle fire in a remote and probably roadless location.)

Chuck (modeling Central Japan in September, 1964)