The Chicago based Diamond T Company had a long history of building heavy vehicles for the US Army for military use and tank transporting, A modified version was also used extensively by the British Army during WWII. The 12-ton half cab 6 x 4 vehicle proved to be one of the most successful in its class, powered by an engine with a maximum 240 bhp capacity. The very low gearing allowed it to pull a trailer load of up to 120,000 lb, the weight of the heaviest tank. After the war, many Diamond Ts were sold into civilian service and would have been just the job for Wynns, the doyenne of heavy haulage at the time and whose haulage activities would have used its strength to maximum effect.

Here we see it as used by Wynns, registered GDW 313 and decorated in their familiar two-tone red livery with black mudguards and chassis. The slogan "Wynns For All Types" is printed in yellow on the cab doors and along the sides, together with the colourful Road Haulage Association crest. An unusual detail sees the front bumper ends and the front part of the mudguard finished in white. The back of the Diamond T featuring tan planking also houses the spare wheel. Wheel hubs match the bright red body colour.

Enthusiasts of this famous South Wales heavy haulage firm will be pleased to add another workhorse to their Wynns fleet.