Mare Island Battery Cart for Submarines, WWII

Came across these today at Seattle NARA and figured I'd pop them up here for the model builders who like dockside dioramas or those just generally interested in Mare Island Navy Yard. Below are photos of a portable charging station for submarines in WWII. The dimensions of the shed were given as a 8' by 24' trailer with the walls being 8' tall at the eaves and 9' at the peak.

Note that the windows on the two back walls are centered while the one closest to the door in the photo is not centered.