Built with a 12 1/2 Set, the O pawls for the rippers and the MF for the fenders are slightly modified. S57 1 3/8 screws are used under the frame to jack the model up so it can operate stationary. 2 Z flanged wheels are used for the upper track wheels. It looks like Maurice has had a lot of fun with his bulldozer. Notice the wear marks on the P13B gear.