Right: It is difficult to see the underbody parts because of all the printing on the tin. The nose of the truck is down. Tinplate parts include a crankcase and transmission, made up of three parts. The drive shaft is 1/8" brass rod, while the braces are 1/16" rod. The exhaust pipe is copper tubing; the muffler and differential were turned on the lathe from brass. The differential isn't actually attached to anythingit is supported by the drive shaft and the rear axle. When the thing is taken apart, the differential just drops off.
Below: The complete cab (sans headlights and radiator cap). You can see the "padding" on the seats. The steering wheel was made of brass wire with a tinplate spider to hold the rim. The roof was gently curved from a flat piece of tinplate and soldered into place. The rear axle assembly is screwed to the frame.