Design Procedures for Walschaerts’ and Stephenson’s Valve Gears Paperback - 39 pages. Author D.L.Ashton ISBN n/a Published by D.L.Ashton

Don Ashton is a recognized expert in the design of valve gears for model steam locomotives and this is a fully revised and updated version of his book first published in 1976. As far as I am aware, this is the only book ever published, solely for model engineers, covering this fascinating subject. There are very few engineers, model or full size, who FULLY understand the workings of these valve gears, resulting in many of the published designs exhibiting minor and even major design faults. As Don points out it is not possible to scale full size valve gear and hope to produce accurate events, even minor errors can result in poor performance. The book covers in detail the design of each component from first principles, using well tried but simple formulae, and includes information on computer simulation and gives worked examples. Most of our models and all full size valve gears were developed without the aid of modern computers, where the proposed design can be computed and simulated in seconds. Model locomotive builders and designers, even full size, will find this a most valuable design manual. A must if ever there was one for IMLEC competitors.

Colin Usher