Tractors made by Wiklng.  Years ago Walthers put them in a sale flier at a small discount so I ordered enough to do the flatcar load.  Took almost a year for them to show up.  They are Fergusons which are nearly dead ringers for the Ford tractors in the photo that Bob Schleicher used in just about every "wish list" article in RailModel Journal magazine.

The Wiking tractors had the exhaust pipe oriented vertically where on the Fords it ran horizonally along the frame.  I moved the pipes (which were delicate and easily broken) and painted the tractors red and gray like the Fords I had seen.

Craig Wilson