Although the Southern Regioning requirement for an austerity 0-6-0 tender goods locomotive resulted from the Board and Operating Department reacting to the increase in freight and military traffic at the time of the Dunkirk evacuation in 1940, with one eye on electrification, cost savings on steam stock had been implemented since 1935. When Oliver Bulleid took over as Chief Mechanical Officer from Richard Maunsell in 1937, he inherited an ongoing order for twenty Q Class 0-6-0 locomotives, which proved less than satisfactory in service and were in no way suitable for the demands of wartime. The answer, for Bulleid and his team, was to start from scratch.
The result that emerged over the next eighteen months was the basic, brutally styled Q1 class, the Charliein-as they came to be known, a locomotive devoid of ancillary furniturein-and reduced to the very bare bones of locomotive design. It had the largest available boiler fitted, was more powerful than the Qin-class and had a greater tractive effort, yet it was barely 1 tons heavier. The distinctive cladding for the boiler was Idaglassin, an early form of fibreglass, constructed over a square steel framework that gave rise to the square tin can look. Designed with free running in mind, essential given its mixed traffic capability, the locomotive performed almost as well running tender first as it did running forward, being capable of a maximum speed of 75mph in both directions.
