CX5. 1937-1939, 1947-1949. The 12 ton six wheel overtype in the CX range was the CX5, available as a 6×2 or a 6×4. This model was offered with EN242, EN243, EN245 and Gardner 6LW engines.
CX21. 1938-1940 / CX23. 1939-1941. The CX21 8 tonner of 1938 and CX23 10 tonner introduced a year later were heavy duty six wheelers with fully articulated double drive bogies designed for overseas markets where much of the running would be over unmade roads. A fleet of such SAR.CX23s owned by South African Railways.
CX29. 1938-1940. The CX29 was a 6×4 model also introduced in 1938, very similar to the CX5, but with a shorter wheelbase, lighter springs and lighter tyres, and designed for loads of 10 tons. It replaced the Model 553, and did not reappear after the war.