GWR 9400 Class
The Great Western Railway (GWR) 9400 Class is a class of 0-6-0 pannier tank steam locomotive, used for shunting and banking duties.
The first ten 9400s were the last steam engines built by the GWR. After nationalisation in 1948, another 200 were built by private contractors for British Railways (BR). Most had very short working lives as the duties for which they were designed disappeared through changes in working practices or were taken over by diesel locomotives. Two locomotives survived into preservation, one as part of the National Collection.
Design
The 9400 class was the final development in a long lineage of tank locomotives that can be directly traced to the 645 Class of 1872. Over the decades details altered, the most significant being the adoption of Belpaire fireboxes necessitating pannier tanks.
The 9400 resembled a pannier tank version of the 2251 class, and indeed shared the same boiler and cylinders as the 2251, but was in fact a taper-boilered development of the 8750 subgroup of the 5700 class. The advantage was a useful increase in boiler power, but there was a significant weight penalty that restricted route availability. The 10 GWR-built locomotives had superheaters but the remainder did not.