While all this scientifically based modernisation was happening on the London & North Eastern Railway, what was the London Midland & Scottish Railway doing? The ‘Claughton’ Class four-cylinder 4-6-0s had been the pinnacle of express locomotive design on the London & North Western Railway and 130 of these elegant locomotives, to many eyes the epitome of Edwardian style, had been built between 1913 and 1921. They suffered from all the worst features of Crewe design philosophy – cheapest construction costs, short-travel valves, lack of attention to detail components, poor lubrication, relatively low boiler pressure (175psi.) and a dreadful ashpan configuration, as mentioned in the previous article. Substitution of the wide Schmidt piston rings (part of the package that came with the superheaters) by multiple narrow ones had improved fuel consumption considerably by eliminating internal steam losses, but the class was still inadequate and uneconomic for the work demanded of it In 1926 No.5908 was fitted with Caprotti poppet valve gear, giving an apparent fuel saving of no less than 27%, and No.5923 was fitted with an enlarged Derby designed boiler with increased air spaces through the ashpan and grate, plus improved piston valves.1 Fuel savings of 17% were now claimed.
Taking these lessons on board, in 1928 twenty examples were rebuilt with the large 200psi Derby boiler, ten of which also included Caprotti valve gear. At last some of the ugly ducklings had been turned into useful swans, which would lay the foundations for the first of the 42 examples of the excellent 5X “Patriot Class in 1930. When William Stanier left the Great Western Railway to become Chief Mechanical Engineer of the LMS in 1932 he was faced with a continuing shortage of locomotives for express passenger and mixed traffic work.
What to do with the remaining 68 unrebuilt ‘Claughtons’? They had at least been allowed to work on some of the important Midland routes, once the civil engineers had accepted that their perfect balance (all four cylinders driving on to a single axle) resulted in zero hammer blow. Stanier already had ambitious plans for a whole range of new designs, so This comment is slightly ambiguous, because in 1932 three examples of the large boiler ‘Claughtons’ (Nos.5908 5912 and 5975 were treated to the same modification.
