Diamond T designed the 730c as a manueverable COE design with high visibilty. IH liked the design so much, they bought the rights to it and it became the early CO series. Powered by either Red Diamond or Black Diamond inline six cylinder gasoline engines ( I think the Diamond T versions may have been powered by a big Hercules 6 cylinder engine or a Continental L head 6), these were the workhorses of the 1950s and 60s. I saw a photo of a Carnation refrigerated distribution truck and couldn't resist the temptation to build one for Trainz.