Letter from J.J.G. Koopmans to Dave Wardale dated 21 July 2005: 21 July 2005© Dear Mr. Wardale, We have exchanged some correspondence in the past. As you may, or may not, remember, I have been busy writing a Ph.D. thesis at the University of Sheffield on the history of steam locomotive front-end development with an […]
A question was asked (by Chris Newman) as to how can it be deduced from Fig 50 (in Wardale’s book The Red Devil and Other Tales from the Age of Steam) that there was scope for an increase in exhaust lap for valves with longer steam lap? The actual wording referred to appears on page […]
Q: Are large (i.e. huge) diameter steam pipes necessary? For example, a smaller steam pipe, provided it has smooth bends, will have less surface area for thermal losses. If the effective delivery of steam to the cylinders is of concern, then can it be solved by having large steam chests or using receivers as on […]
In Oct 2007, John Tasker wrote to ask if steam jacketed cylinder had been considered for the 5AT. He suggests that when a loco is stationary a steam jacket would help reduce thermal losses when starting from cold. Dave Wardale offered the following response: “Cylinder steam jacket. This has been well explained by Porta. It […]
Dave Wardale offered the following responses to questions put to him relating to his Fundamental Design Calculations for the exhaust system [FDC 12]. (See also Wardale’s Notes on FDC 12.) Blower nozzles: I had always imagined that blower steam was simply exhausted up the chimney through the blast pipe when no exhaust steam was available […]
Note: The subject of 5AT reliability is also discussed briefly in the 5AT Features section of this website. In Sept 2009, David Wardale wrote a lengthy letter in response to a question about the thermal efficiency of the 5AT in comparison with other “modern steam” designs. He wrote as follows: FDC 1.3.F.[114]: Drawbar thermal efficiency […]
Note: The subject of 5AT Reliability is also described in the 5AT Features section of this website. The following summary of 5AT “reliability factors” was compiled by David Wardale in March 2005.Design features leading to a much higher reliability of the 5AT Class steam locomotive compared to First Generation Steam (FGS) Locomotives. The advanced technology […]
he following answer is taken from Wardale’s response to Leonard Staghurst whose letter was published in Steam Railway #277 (copied below): “Unfortunately Mr. Staghurst’s comments betray his lack of knowledge, not only of what is possible with steam traction but also of what has already been achieved. Consider the following. The above figures, which are […]
Wardale strongly defends his choice of Walchaerts valve gear and piston valves, and has explained his reasons in several letters, some of which are included in the page titled “Why Walschaerts Valve Gear?”. However a more comprehensive reply is recorded in a letter from David Wardale to John Duncan which is transcribed over 7 pages titled “Piston […]
Chris Newman posed the question: “Why were piston tail rods dropped from latterday designs?” Wardale responded as follows: “Without a tail rod the weight of the piston is taken by its head or by the rings if these are of lipped type. They were dropped because head and linear wear was found to be tolerable […]
Readers have occasionally asked whether consideration was given to applying variable lead to the Walschaerts valve gear on the 5AT. In fact, Wardale did give thought to this and he discusses it in FDC 5 (line 34) where he wrote: Varying lead with cut-off is possible by shortening the eccentric crank length or slotting the […]
The following answer is taken from Wardale’s response to an unpublished letter from Bryan Attewell written in response to Wardale’s two-part article “Steaming into the Future” published in Steam Railway magazines #272 and #273: “Mr Attewell criticises the choice of 2 cylinders for high speed, but the 2-cylinder locomotive cannot be simply condemned without fully […]