All Prairies large and small!

THE history of the GreatWestern Railway’s 2-6-2 tank locomotives, normally referred to as Prairies, began in 1903 with George Jackson Churchward’s prototype Prairie tank, No. 99. The working pressure of its Standard No. 2 boiler was 200psi, which, together with the locomotive’s two 18½in x 30in outside cylinders and 5ft 8in diameter driving wheels, combined to produce strong performances during extended trials that were conducted over the following two years.

It set the pattern for a further 39 large Prairie locomotives constructed in 1905 and 1906, whose only real difference was that they featured sloping rather than flat-topped tanks for greater visibility. This batch carried the running numbers 3111 to 3149, and in 1912 the prototype was renumbered 3100.

So successful were the large Prairie tanks that they continued to be built until 1949, when the final 20 were constructed under British Railways, but the story became more complex over the years with various modifications and class numbering sequences.

Larger Prairies

In 1907, larger standard No. 4 boilers working at 200psi