As with all Standard steam locomotives the tanks were the last of a long line of development dating from the earliest years of steam. The three classes covered in this volume – Class 4MT 2-6-4Ts, Class 3MT and Class 2MT 2-6-2Ts were all developments of existing designs for the LMS and GWR. In almost all cases they were responsible for the side lining of various pre-Grouping designs that served their companies well for several decades. The Standards were, alas, to last less than 20 years, some not even serving BR for a decade. The Standard ‘4s’ were allocated to London Midland, Scottish and Southern Regions, the Western Region receiving them towards the end of steam. The ‘3MTs’ were generally limited to Southern and Western Regions, although some did head for the North Eastern Region at Malton. The Class 2s did most of their work on the London Midland and Southern Regions. The Standard tanks were a brave attempt to up-date the working of stopping trains in the UK, and although they were a good investment the tragedy was that they came too late – their service life being cut short by the Beeching Report and modernisation.