The TR RV class, later known as the EAR 21 class, was a class of 1,000 mm (3 ft 3 3⁄8 in) gauge steam locomotives designed and built for the Tanganyika Railway (TR) as a 4-8-2 development of the 2-8-2 TR MK class. The eight members of the RV class were built by Vulcan Foundry, in Newton-le-Willows, Lancashire (now part of Merseyside), England.The "RV" class designation was short for "River", as each RV class locomotive was named after a river in the Tanganyika Territory.