Because It's Friday

A Decauville railroad.

Decauvilles were narrow-gauge light rail. The tracks could come pre-fabricated, like giant Lionel-type segments. The tracks could be laid very quickly. The Decauville system was widely used for constructing railroads for moving ammunition, supplies and cannon fodder up to the trench lines during the Great War. Possibly the very first internal combustion locomotives ran on the Decauville trench railroads, as steam engines created too much smoke and thereby attracted the unwanted attention of German artillery spotters.