North Eastern Railway Raven 'S2' (LNER 'B15') class 4-6-0 No. 825. Built at Darlington in March 1913 fitted with 'Stumpf Uniflow' cylinders, rebuilt with standard cylinders in March 1924 and withdrawn in February 1944.

The strange and fascinating cylinder arrangement of 825 owes its appearance to the experimental use of Johann Stumpf's 'Uniflow' cylinders. Steam was admitted at one end of the cylinder, and the used steam left through a ring of ports at the other end. Stumpf's system worked well enough with modest economies in fuel consumption. The downfall was that like many experiments in improving locomotive economy, the build and maintenance costs were greater than the savings and/or efficiency achieved!

© Steve Armitage Collection