Highland Railway Clan Class

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HR Clan class
Power type Steam
Designer Christopher Cumming
Build date 1919 (4), 1921 (4)
Driver size 72 in (1.829 m)
Locomotive weight 63.25 long tons (64.26 t)
Boiler pressure 175 psi (1.21 MPa)
Fire grate area 25.5 sq ft (2.37 )
Cylinders Two (outside)
Cylinder size 21×26 in (533×660 mm)
Valve gear Walschaerts
Tractive effort 23,688 lbf (105.37 kN)
Career HR, LMS, BR
Class LMS: 4P
Number in class 8
Number HR: 49, 51–57
LMS: 14762–14769
BR: 54767
Retired 1944–1950
Disposition All scrapped

The Highland Railway's Clan Class was a class of passenger 4-6-0 steam locomotives designed by Christopher Cumming. The design is derived from that of the slightly earlier Clan Goods although the similarity is more visual than real.

They had 21 inch by 26 inch cylinders outside with outside Walschaerts valve gear, 6 ft 0 inch driving wheels and a boiler pressured to 175 lbf/in² (1.2 MPa). Weight was 62 tons 5 cwt (63.25 t) for the locomotive and 42 tons (42.7 t) for the tender. Piston valve diameter is given as 10 inches (quite large for the period), but they had the conventional short lap, short travel valves. Bearing in mind that they probably spent a large part of their time slogging uphill or coasting down this was probably not too important.

Total heating surface (including superheater) is given as 1723 sq feet and grate area as 25.5 sq feet. The first four were built in 1919, and the remaining four in 1921.

HR Number LMS Number Name
49 14762 Clan Campbell
51 14763 Clan Fraser
52 14764 Clan Munro
53 14765 Clan Stewart
54 14766 Clan Chattan
55 14767 Clan Mackinnon
56 14768 Clan Mackenzie
57 14769 Clan Cameron

Two survived into British Railways hands, but only Clan Mackinnon received its BR number.

Early in 1921 Clan Stewart was used for experiments with oil firing. They seem to have been successful, but was not applied to any other locomotives. Just when Clan Stewart reverted to coal operation does not seem to be recorded.

The LMS classified them '4P'.

The Clan names were later reapplied to the BR standard class 6.

[edit] References

  • Casserley, H. C.; Stuart W. Johnson (1966, 1974). Locomotives at the Grouping 3, London Midland and Scottish Railway location=Shepperton, Surrey. Ian Allen Limited. ISBN 0 7110 0554 0.