Discussion in 'Locomotive M.I.C.' started by huochemi, Mar 6, 2019.
May be a dumb question but do slide valve locos ever have superheating?
I stand to be corrected by I think the Dukedogs do?
The Drummond T9 as rebuilt by Urie would be an example.
Ffestiniog Fairlies, plus Linda, Prince, and Lyd.
Thank you for the examples.
Bulldogs were piston valve fitted.
There were numerous examples among pre-grouping classes on the GSR over in Ireland. Several locos, at some point or other fitted with superheated boilers, even reverted to saturated steam, this seemingly having more to do with what happened to be available, boiler-wise, rather than any fixed policy.
Retention of slide valves on superheated locos was, in the Irish case, a direct result of perennial shortage of funding during the whole existence of the GSR (1925-45), continuing until the final run down of steam by the CIÉ during the mid fifties to early sixties.
Most Great Eastern D16 4-4-0s retained slide valves with superheaters.
The sole remaining superheated slide valve locomotive that I am aware of is GWR Collett goods 0-6-0 number 3205, which is presently out of service on the South Devon Railway. The boiler is a GWR number 10, the same boiler was used on the 15xx class and 94xx class but apart from the first 10 of the 94xx class the others were not superheated.
In Churchward's day many of the inside cylinder locomotives with double frames were superheated and also had slide valves for a period of time, however these slide valves were the balanced type which had less load on the working surfaces. Both City of Truro and the Dukedog now have replacement cylinders with piston valves.
Edit. There may be others remaining in preservation era but I am not aware of them (until now!).
(Martin Stone from Reading, United Kingdom [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)], via https://commons.wikimedia.org/wiki/File:LSWR_T9_Class_No_30120_and_5164_(8518145783).jpg)
Superheating + slide valves wasn't that uncommon in the Edwardian era, when designers were getting to grips with the transition from saturated to superheated and slide to piston valves more or less simultaneously (with the attendant lubrication issues); and also possibly re-boilering older saturated locomotives to extend the life and extend the capabilities. Another example to add to the list were the Marsh H1 Atlantics, which were built saturated + slide valve, but later took on superheated boilers of the same pattern as the H2 Atlantics while retaining the slide valves.
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