Highland Railway Clan Class
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 Class|Clan Goods] although the similarity is more visual than real. The first four were built in 1919, and the remaining four in 1921.
Dimensions
They had cylinders outside with outside Walschaerts [valve gear], driving wheels and a boiler pressured to. Weight was for the locomotive and for the tender. Piston valve diameter is given as , 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 evaporative heating surface is given as, plus for the Robinson [type superheater], and grate area as.Oil firing
Early in 1921 Clan Stewart was used for experiments with Oil [burner (engine)|oil firing]. This seems 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.Transfer to LMS
The locomotives passed to the London, Midland and Scottish Railway in 1923.The LMS classified them '4P'.