Designed by Deeley and introduced in 1903, these were the 3F Class 0-6-0 tender locomotives of the Midland Railway, some rebuilt from earlier 2F 0-6-0 types. Like all 3F Class locomotives, they underwent considerable rebuilding during their lifetime and were seen all over the former Midland Railway system. In 1923, 482 of the locomotives passed into LMS ownership. They were the forerunners of the larger superheated 4F class, introduced by Fowler in 1911.

3F Class locos allocated to the Somerset & Dorset Joint Railway may be identified by their possession of an additional front sand box. As originally built, the locos had round top fireboxes but Fowler had them all rebuilt, fitting boilers with Belpaire fireboxes and larger cabs. Ross pop safety valves later replaced the original Salter valves.

They were used almost exclusively on goods trains, sometimes running double headed in MR days, for heavier trains. The locos lost much of their work in the early 1960s with the closure of many branch lines and collieries and the introduction of diesels. The 3Fs enjoyed a long life, the last remaining in service until 1964. Sadly, none of them was preserved.