Power of the ‘Georges’
Keith Farr looks back to the heyday of the London & North Western Railway and its successor the LMS, and analyses performances of ‘George the Fifth’ as well as other classes on the West Coast Main Line.
For this month’s Practice & Performance
Keith Farr rolls the clock back to the heyday of the LNWR and analyses the performance of its famous ‘George the Fifth’ class 4-4-0s.
Pontllanfraith (Low Level) station in Monmouthshire was a tranquil place that summer’s afternoon in 1958. True, a ‘56XX’ 0-6-2T had just pulled out with a train from Neath to Pontypool Road; but that was as nothing compared with the sudden explosion of exhaust from a ‘Super D’ 0-8-0 battling uphill through the nearby High Level station on the Sirhowy Valley line with a load of ‘empties’.
I had previously seen former LNWR 0-8-0s at Watford, Bletchley and elsewhere, but never before had I witnessed one in full cry.
Its two-cylinder exhaust beats, four for each cycle of the coupled wheels, had comprised two very loud blasts followed by a softer pair; apparently, this phenomenon was typical of a ‘Precursor’ or ‘George the Fifth’ 4-4-0 going up Shap at a slightly higher speed but, because of their larger coupled wheels, with exhaust beats sounding at about the same rate.
Now for some history: 1903 found Francis Webb, a sick man, relinquishing the post of LNWR chief mechanical engineer (CME) under the cloud of his partly unsuccessful ventures into compounding.
Benefited
Admittedly, the later ‘Compounds’ had benefited from having coupled driving wheels and four cylinders, two of them low pressure and two high pressure, and each pair independently controlled by the driver. Such features enabled Alfred the Great, a 52-ton four-cylinder compound 4-4-0, to haul 480 tons gross over the 77 miles from Rugby to Willesden in 85min 42sec.
Nonetheless, the earlier three-cylinder Webb
Compounds in particular were erratic, with high running costs, and an edict that all trains equivalent to 17 or more six-wheeled coaches should be double-headed led to a slaughter of motive power by Webb’s successor, George Whale. Something simple and robust was needed to replace the Compounds and reduce the expensive double-heading that had become rife, something on the lines of the ‘no-nonsense’ ‘Cauliflower’ 0-6-0s and ‘Jumbo’ 2-4-0s, only larger.
The result was No. 513 Precursor, the first of 130 straightforward inside-cylinder 4-4-0s outshopped from Crewe between 1904 and 1907. With a deep firebox and 2,009.7sq ft of heating surface, the ‘Precursors’ could be flogged up to Tring and even over Shap, despite their lack of superheating and use of slide rather than piston valves.
Nonetheless, a six-coupled loco was deemed more appropriate for the northern fells and, in 1905, Whale produced No. 66 Experiment, a 4-6-0 version of the ‘Precursors’.
However, the 6ft 3in coupled wheels of the ‘Experiments’ were closely spaced, with the first pair under the 25sq ft grate, which therefore had to be higher and less deep than the
22.4sq ft grate of the 4-4-0s, but once firemen had learned the technique of creating a thin fire they were able to economise on fuel, particularly on the gentle gradients south of Crewe.
The overall heating surface of an ‘Experiment’ was only marginally greater than that of the ‘Precursors’, while the slightly increased distance between front and rear tubeplates would have weakened the draught on the fire. Despite their 6ft 3in coupled wheels, the 4-6-0s were fast downhill but, paradoxically, inferior to the 6ft 9in 4-4-0s on the banks. Charles Rous-Marten, first author of this performance series, timed Experiment down Shap at 93mph; it would be unkind to suggest he was in the habit of attributing unrealistically high speeds to inside-cylinder 4-4-0s, in Somerset for example.
Whale retired in 1908 to be followed as CME by C J Bowen Cooke who, like Churchward on the GWR, kept his eye on practices elsewhere. Before his Crewe apprentice days, he spent a year at Neuwied on the Rhine, developing his interest in German engineering and, particularly, the work of Dr Schmidt, an expert on locomotive superheating.
Nearer home, on the London, Brighton & South Coast Railway, Douglas Earle-Marsh had produced a Class I3 4-4-2T with a Schmidt large superheater, prompting Bowen Cooke to mastermind an exchange trial in June
1909 between his saturated ‘Precursor’ No. 7 Titan and an I3 on the ‘Sunny South Express’ between Brighton and Rugby.
Advantages
Admittedly with only 250 tons, LBSCR 4-4-2T No. 23 completed the 264-mile return working from East Croydon to Rugby without replenishing its bunker en route and consuming just 27lb of coal and 22 gallons of water per mile. The LNWR comparator, the 4-4-0 Titan, played with the load but its fuel consumption was higher; had the train been heavier, the result might have been different. For Bowen Cooke, the advantages of high superheat were now obvious and he produced two 4-4-0s in the ‘Precursor’ mould, one superheated, the other not. Completed in July 1910, No. 2663 George the Fifth had a Schmidt superheater and 20in x 26in cylinders, while 2664 Queen Mary had no superheater and 19in x 26in cylinders. The two prototypes had identical front-ends with piston valves, but extensive trials found the high superheater George the Fifth burning some 26% less coal than Queen Mary. Nine more ‘Queen Mary’s were built, proving superior in performance to the original ‘Precursors’, but not quite up to George the Fifth standard. The success of the ‘Georges’ themselves stemmed primarily from the 24-element superheater with 302.5sq ft of heating surface backed by a modest 1,358.4sq ft from 168 boiler tubes, providing a high superheat/boiler tube ratio. Other factors were the combination of a boiler short enough to minimise heat loss between the rear and front tube plates, a large