The Prince of Wales Tanks were 47 4-6-2T tank locomotives which Charles Bowen Cooke had built in Crewe between 1910 and 1916 for the LNWR. As their name suggests, they were referred to as tank versions of the Prince of Wales Class. However, they were more closely related to the Precursor Tanks, which had one less driving axle. They were also known as class 2665 after their running numbers and also as “5ft 6in Tank (Superheated)”.

Twelve locomotives were built without superheaters, but were rebuilt after a short time. The area of operation included, among others, suburban trains from London-Euston. Since the axle load was lower than that of the Precursor Tanks, they could be used more freely. This was the case, for example, on a 120-mile route in Wales. They all came to the LMS in 1923 and were decommissioned there between 1935 and 1941. Their successors were the 2-6-4T tank locomotives designed by Fowler and Stanier.