The North Eastern Railway's class D was developed by Vincent Raven for rural passenger trains. In order to achieve equally good running characteristics in both directions of travel, he chose a tank locomotive with a 4-4-4T wheel arrangement. Three cylinders ensured smoother acceleration. Although there were only two axles available for traction, the coefficient of adhesion of more than four indicated that there was enough traction for starting without slipping.
In 1913 the first 20 were built in Darlington. Another 25 followed after the war in the years 1920 to 1922. The LNER took over the locomotives as class H1. Between 1931 and 1936, all were rebuilt to a 4-6-2T wheel arrangement. These were designated class A8 and were retired between 1957 and 1960.