In 1938, Hornby Dublo (‘00’) was launched. This was approximately half the size of the ‘0’ gauge system. The new locomotives had cast metal bodies rather than pressed metal, and the buildings were made of wood. Both clockwork and electric sets were available before the Second World War, although these were limited to Sir Nigel Gresley, an LNER A4 Class Pacific, and an LNER Class N2 tank locomotive in the liveries of the ‘big four’ companies of the time (GWR, LMS, LNER and SR).
Production stopped during the Second World War (1939 - 1945) but Hornby Dublo soon reappeared once the war was over, although without a clockwork range. By the late 1950s, it was clear that Hornby Dublo was losing ground to its competitors and changed from a three-rail system to the established two-rail track system in 1959.
Hornby came under increasing pressure from rival company Tri-ang Railways, who had developed plastic bodied trains and carried out its manufacturing at a purpose-built factory in Margate, Kent. Hornby Dublo and Tri-ang Railways rivalled each other during the early 1950s and following the acquisition in 1964 of Meccano Ltd was taken over by Lines Bros (the parent company of Rovex Scale Models Ltd, manufactures of Tri-ang Railways), in 1965 and became Tri-ang Hornby.
Production of Hornby Dublo ceased in 1964 and some of the tooling was purchased by G&R Wrenn Ltd (another subsidiary of Lines Bros.) to launch Tri-ang Wrenn in 1967.