Bagnall-Price valve gear
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Bagnall-Price valve gear is a type of steam engine valve gear developed at locomotive manufacturer W.G. Bagnall as an alternative to the more common Walschaert valve gear. The gear was patented in 1903 by W.G. Bagnall and T. S. Price, the manager of the works.
[edit] Layout
The valves are driven from an eccentric cam mounted on one of the driving axles and linkage from the crosshead. The driving axle cam drives a rocking shaft that is mounted inside a cylindrical sleeve (known as the rocking shaft bush) above the cylinder. A drop lever and connecting link from the crosshead oscilates the sleeve to control the lap and lead of the cylinder.
[edit] Comparison to Walschaert
W.G. Bagnall claimed that Bagnall-Price valve gear eliminated some of the complexity of Walschaert gear, specifically the combination lever and return gear; this in turn meant the externally mounted gear had greater ground clearance which was an advantage in industrial locations where lineside obstructions could damage the gear of passing locomotives.
[edit] References
- Fairburn, Mike. "Bagnall Price Vavle Gear". The Journal of the Welsh Highland Railway (121).
- Baker, Allan C. (September 1966). "Bagnall Locomotive Valve Gear". The Industrial Railway Record 11: pp.264-270.
