Caprotti valve gear [SEP] named after
Caprotti valve gear
The Caprotti valve gear is a type of steam engine valve gear invented in the early 1920s by Italian architect and engineer Arturo Caprotti. It uses camshafts and poppet valves rather than the piston valves used in other valve gear. While basing his design on automotive valves, Caprotti made several significant departures from this design to adapt the valves for steam. Having agreed a joint-venture with Worcester-based engineering company Heenan & Froude from 1938, Heenan & Froude fully acquired Caprotti post-World War II in 1947
the bogie wheels of predecessors Classes 19 and 19A fouled the cylinder covers on sharp curves. The longer wheelbase bogie also facilitated the removal of cylinder covers at running sheds. Because of this difference, the new engines were designated Class 19B.
The first thirteen Class 19B locomotives were delivered with Walschaerts valve gear, but like Class 16DA no. 879 of the same year, no. 1414 was equipped with Caprotti valve gear as an experiment. In January 1943, after thirteen years in service, the Caprotti rotary cam poppet valve gear