The truck is a standard cargo truck with a locally fabvricated collapsable wood shelter over the cargo bed. These were designed to telescope down to reduce the height of the vehicle if it was to be stowed on a ship. uses included but were not limited to, supply tyrucks, mess trucks, various office trucks or maintenance trucks.
When raised there would be enough room to stand up under the roof. You could not put anything high in them that would prevent the roof from going down to the lowered position.