Looks like the truck was used as a crew car with the portable steps and seats in back. Note the train order board on the station at the left edge of the photo. I wonder if the truck was turned or they ran backwards in one direction.
Steve, I wonder about those wheels too. What type of car (or boat launch?) did they come from. The truck should have tracked well with heavy cast wheels but I don't see any brake shoes. They must have relied on the foot brake which on a Model T is in the transmission. On RC4 we use both the foot and hand brakes.