The Plymouth Locomotive Works, which specialized in the production of smaller diesel locomotives between 130 and 300 hp, offered the larger CR-8 in the sixties to round off their program upwards. In terms of size and basic design, it roughly corresponded to the GE 44-tonner, but the transmission was hydraulic. The locomotives were offered for gauges between three and 5.5 feet and were in a weight range between 45 and 65 short tons. The two engines together delivered between 400 and 1,000 hp. 

A variant came to Thailand in 1963 and was used shortly afterwards by the US Army in the Vietnam War. These locomotives weighed 52 tons and made 500 hp. After the war they came to the Vietnam Railways and were classified as Class D10H. Other locomotives of the Chinese type DFH21 were also listed as D10H.

In the USA, the different variants of the CR-8 were used by different industrial companies with heavy loads to be moved. Parallel to the CR-8, the manufacturer offered the CR-8XT, where XT stood for “eXTra Tonnage, eXTra Power, eXTra Performance”. This was offered with weights between 70 and 120 short tons and also had two engines with a total of between 650 and 1,400 hp.