The wheels and axles where mounted on bearings which were attached to the journals.  The levers and rods to operate the brakes and direction/speed were made and painted.

The journals where built up from 1/4" bar stock.  You can see in the picture below the 2 tabs on the journals (like the ones on the frame) to hold the springs.  The journals are kept from sliding off by a bolt (below right) that sticks out and catches the tab on the journal.  You can see the tab on the journal on the picture above.  Makes it real easy to remove the axles/wheels.

The engine selected was a Briggs & Stratton 5.5 HP with electric start.  The transmission is a Tecumseh hydro-static.  A similar setup was used in my wood switcher and it operates excellent for this application.  They are connected via a belt.

Had a bit of wiring to do like the starter, charger, lights, compressor, switches, battery, etc.

This is the underbelly showing the drive chains, exhaust, etc.

Here's the frame and drive system completed.  The air tank was mounted on top of the console and put the pull starter (backup) on top of that.