Aviation Specials Magazine Sulzer Power Special Issue

Welcome to this special publication dedicated to the Sulzer-powered locomotives that served Britain’s railways from the late 1950s. The Swiss engineering company Sulzer had a long history developing diesel engines and was an early exponent of marrying the technology to rail transport. Its work before World War Two stood it in good stead after the conflict ended in 1945 and it was soon supplying diesel engines of varying sizes to railways in Europe and around the world.

With the publishing of British Railways’ 1955 Modernisation Plan another huge opportunity arose and Sulzer found itself providing hundreds of power units for Type 2, 3 and 4 locos well into the 1960s. Its engines were only matched in number by its main rival in the UK market, English Electric. A notable difference between the two was the engine configuration, with EE favouring the V layout while Sulzer preferred an in-line cylinder arrangement. To produce more powerful engines developing more than 2,000hp for Type 4 locos, Sulzer chose to put two in-line six units side by side to create a 12-cylinder unit that drove a single output shaft to turn the generator. This did produce a heavy power unit, and made some components difficult to access for maintenance, but the low-revving four strokes were very reliable, particularly those fitted to the British Railways’ Peaks and in the Class 47, once they were de-rated.

Today the only Sulzer-powered locos still regularly active on the main line are some Class 47s, although a handful of Class 25s and 33s can be seen on the network, while plenty more, including 26s and 27s, can be found active in preservation. That is quite remarkable given most are approaching 60 years old and is testament to the engineering and near bulletproof design of the Sulzer diesels.

Mark Nicholls, Editor, Railways Illustrated