Bob Burkhouse tests his 1950 Cletrac AD diesel tractor on the dynamometer at the Williams Grove Historical Steam Engine Association show in Williams Grove, Pennsylvania on September 6, 2009. Cletracs and Oliver tractors were the featured manufacturer this year.
http://www.youtube.com/watch?v=Dq6iml6k5cU (http://www.youtube.com/watch?v=Dq6iml6k5cU)