The Tractor & Truck Trailer Car No. 6431 was only available in 1966. It was produced in a brighter RED than the previously issued No. 6430 and came in a unique picture box that also housed a die-cast Midgetoy tractor. This tractor is marked on the inside of the roof: "MIDGE TOY / ROCKFORD ILL. / U.S.A. / PAT / 2775847". Note that the car is numbered "6430," and that the number "6431" appears only on the box end for this car. Came with AAR trucks with disc couplers.

Came with two Type 10 or Type 11 trailers. There are three variations:

Variation A: RED uses flat car chassis mold No. 6511-2.

Variation B: Identical to Variation A except uses mold No. 6424-11.

Variation C: Same as Variation B, but with frame rail extensions on a No. 6424-11 flat car mold.

Collectors should be aware that this car and its load are often found with a No. 6430 DARK RED car and a reproduction tractor. Always check for the inscription on the inside roof of the tractor.