The SR Merchant Navy class (informally known as Bulleid Pacifics, Spam Cans or Packets) were designed for the Southern Railway by Oliver Bulleid. First of the class were built during World War II, and the last of the 30 locomotives in 1949. The class members were named after Merchant Navy shipping lines.

Incorporating much technological innovation, the design of the Merchant Navy class was among the first to use welding in construction which allowed easier fabrication of components during the austerity of the war and post-war years. In addition, the locomotives featured thermic syphons and controversial Bulleid chain-driven valve gear. Problems with elements of the Bulleid design, meant that all of the class were modified by British Railways during the late 1950s. Rebuilding the class solved most of its maintenance problems, but retaining the best features and resulting in excellent locomotives.

On 26 June 1967, 35003 Royal Mail recorded the highest speed for the class. Hauling a train comprising three carriages and two parcels vans  between Weymouth and Waterloo, a mile was covered in 34 seconds, a speed of 105.88 mph, the last authenticated speed in excess of 100 mph achieved by a steam locomotive in the United Kingdom until the run by Tornado in 2017.

The Merchant Navy class operated until the end of Southern steam in July 1967. No less than 11 of the class have survived and can be seen at various  heritage railways.

This fine model was built in 5” gauge by J Richardson and attracted much attention at a National Model Engineering and Modelling Exhibition in its Harrogate days.

Keith Wilson produced detailed drawings for Ariel, a rebuilt Merchant Navy class loco which are available here.