This reminds me of when I was a kid in the 50s, and being excited seeing intrepid drivers whizzing along with goggles on and sitting on loose-lying wooden boxes, ferrying fully functioning engine/chassis' combinations to a coachbuilder, to be mated with new bus bodies. Yes, I am very old.
![Grin ;D](https://www.autopuzzles.com/forum/Smileys/default/grin.gif)
The puzzle bus looks German.