In common with most British locomotive builders, in the postwar era Kerr, Stuart received a number of large orders from the mainline companies who were seeking to replace obsolete inherited equipment with their own standard designs. In 1920 the Metropolitan Railway ordered eight superheated 4-4-4 passenger tank engines for the Aylesbury service. Between 1925 and 1927 the Stoke works built fifty standard class 4F 0-6-0 goods engines for the London Midland and Scottish Railway and in 1929 and 1930 a batch of 25 GWR 5700 Class 0-6-0PTs were built for the Great Western Railway.