Here's a couple of more shots of Stromboli's wagons about to be filmed by Bob Jones and the gang in the Model Department. These models were built by Bob Jones and Wah Ming Chang.
After the wagons were filmed going down a simulated cobblestone road, they were rotoscoped, which involved projecting the live-action photos frame by frame onto a transparent panel, through which they were traced.
My friend and fellow researcher Dennis Books says, "Walt improved the system by having each frame of film printed onto photographic paper the same size as the drawing paper. These photostats were then punched to fit the pegs of an animation desk. The animator could now study or draw the action by flipping the photostats."