Indian locomotive class XB

The Indian locomotive class XB was a 4-6-2 Pacific passenger locomotive with a 17-long-ton axle load, one of several standard designs drawn up in the early 1920s for the Indian Railway Standard series. The Indian Railway Board formed a Locomotive Standards Committee in 1924 to respond to growing traffic after the First World War and to the prospect of burning low-grade coal, and it drew up three Pacific passenger classes and two 2-8-2 freight classes with the British Engineering Standards Association. The XB suffered frame fractures, coupling rod failures and a weak boiler, and after the 1937 Bihta derailment, which killed over 100 people, stiffer springs and speed limits were adopted. XBs ran until the 1980s, and No. 450 is preserved at Lahore. Armstrong Whitworth built twelve.