© Don Marshall 2016
Class A1 No 2555 Centenary.  The LNER A1 Class was a continuation of the A1 Class Pacifics originally introduced in 1922 for the Great Northern Railway. Designed by Mr Nigel Gresley they were a powerful addition to the LNER stock of mainline express locomotives and replaced the Atlantics on mainline duties. Following a locomotive exchange with the Great Western Railway against their Castle Class 4-6-0's some shortcomings were revealed. Design changes were made and, though they were not extensive,  the result was the A3 Class of Pacifics that were the mainstay of East Coast mainline running until 1964. No 2555 Centenary was built in 1925 and was not converted to Class A3 until 1944. In fact, the majority of the Class was not converted to the A3 specification until BR days.
The practice of placing LNER and the engine number on the side of the tender only lasted until 1928 when the number was placed on the cabside. (see illustration of A3 Windsor Lad). This obviously made sense as the tender could not be used when the locomotive was in for repair. Photos do exist of locomotives with one number hauling a tender with an entirely different number !
London & North Eastern Railway