When the Sno-Train manufacturing was completed, it was sent to Houghton, MI for the Army to test capabilities. In the image shown below, you see two personnel checking trailer connection or power cables. The large pill-shaped canister between the rear tires is the fuel tank. This photo also shows the Sno-Train with traction lugs attached.
Traction lugs are the equivalent to tire chains, but they are for the monster 120x48x68 tires. Seen below is the diagram showing the Overland Mark 2 traction lugs, which vary from the lugs seen above. R.G. and his engineers iterated on many of the designs as they learned more about how they operated in field conditions. The traction lugs were one of those iterative devices.