Instead of ordering another batch of the class 1185 with a 0-8-2T wheel arrangement, H.P.M. Beames developed the class 380 with a two-axle trailing bogie to get more space for the supplies. Their area of application was the steep and winding lines in the valleys of South Wales, on which they were to pull freight trains and, if necessary, also be used in front of passenger trains. When the locomotives were delivered, the LNWR had already been merged into the LMS, where they were classified in power class 5F. 14 of the 30 locos survived the founding of British Railways, but these were retired by 1951. 