Francis Webb developed the 17 inch coal engine in the early 1870s as his first design for the LNWR. It was created under the requirement that production and operation should be as cheap as possible. These three-axle machines were sometimes described as the simplest and cheapest in the country, but on the other hand they were generally extremely successful with typical British maintenance. A total of 499 were built in 19 years.

One locomotive demonstrated that it could be built, including building up steam, in 25.5 hours. They could pull coal trains of 541 tons at a speed of 25 mph. From 1905 onwards, 45 were rebuilt into saddle tank locomotives. During the First World War, many were used by the military abroad, some even in Palestine. The LMS took over almost half in 1923, the British Railways received 35 in 1948 and used the last until 1953.