Co+Co Co+Co is the code for a similar wheel arrangement but with an articulated connection between the bogies. The buffer and drawbar forces are taken between the bogies rather than through the frame. These were mostly popular in South Africa. 1Co-Co1 The 1Co-Co1 wheel arrangement is an alternative to the Co-Co arrangement which has been used where it was desired to reduce axle load. Each "Co" bogie has an additional non-powered axle in an integral pony truck to spread the load. As the pony truck is articulated within the bogie, the arrangement is (1′Co)(Co1′) in UIC notation. This rare arrangement was used primarily in Britain; on the Southern Railways' first three prototype mainline diesel-electric designs, 10201–10203, and then on production vehicles in British Rail's Class 40 and "Peaks" (BR classes 44, 45, and 46). 1Co+Co1 1Co+Co1, like Co+Co, is an articulated variant where the drawbar forces are taken between the bogies rather than through the frame. These were used in South Africa, for lighter loadings on the lightly laid . A number of Japanese electrics from the 1930s, also on Cape gauge, such as the EF10 also used this arrangement. 2Co-Co2 The New Zealand DF class were built in the mid-1950s by English Electric in Britain, as the first diesels for the New Zealand railways. They were derived from the earlier English Electric 1Co-Co1 bogie design, but to provide increased flexibility for the long wheelbase bogie they used a four-wheeled bogie with more sideplay, rather than a pony truck. See also Co-Bo, which has two uncoupled bogies References Co-Co CC,Co-Co