Great Central class 13

The Great Central Railway Class 13 was the last single-driver express locomotive to be built in Britain and one of the last to see regular service. It was developed by Harry Pollitt, who called it Type X4. It had 7 feet 9 inches diameter wheels and had a boiler pressure of 200psi from the factory. Since, despite the sophisticated sanding system that was obligatory on the last singles, there was more power than could be converted into traction, the boiler pressure was soon reduced to 160 psi. 

When Pollitt retired in 1900 and John G. Robinson took over as chief engineer at GCR, the class 13 was just being produced. Anticipating the imminent end of the singles, Robinson reduced the order from ten to six. These locomotives initially ran the important route from Sheffield to London, but were moved to Cheshire in 1903 and replaced by the 4-4-0 Robinson class D4 locomotives. Four examples were fitted with a superheater between 1915 and 1919, but they were all retired between 1923 and 1927.