THE FRATERNITY OF GIANTS

SIR NIGEL GRESLEY (1876-1941)

We are accustomed to certain concepts of British anti-French prejudice as being as reliable as if cast in steel. These ideas go back even centuries. And the more "Establishment" the British person is, the more lively the prejudice we expect.

Now in the pre-WW II era there was no mechanical engineer in England more celebrated than the great Sir Nigel Gresley. He was the Chief Mechanical Engineer of the London and North Eastern Railway (L.N.E.R.) and designer of many locomotives but of greatest note for his A4 Streamlined Pacifics especially their class member "MALLARD" at the time, the fastest steam locomotive in the world at 126mph, although Sir Nigel Gresley only accepted 125mph!

                                                   L.N.E.R. A 4  MALLARD

But the brotherhood of Mechanical Engineers exceeds the power of national prejudice. There was another, greater Mechanical Engineer in France: Andre Chapelon. Unlike Sir Nigel Gresley, this genius was relatively frustrated by his administrative superiors, and, unable to get approval to build many new locomotives according to his ideas, he had to content himself with re-building existing locomotives. This he did with remarkable brilliance, which was acknowledged by his peers around the world, but treated as an embarrassment by his superiors. Chapelon was among the earliest champions of a scientific approach to the detail of locomotive design and performance, which had up to that time, been largely pragmatic being based on trial and error -  evolution from previous practice.In 1925 Gresley was so impressed by what he read of  Chapelon's work that he went to France to visit him and consult him. When he returned to England he put in hand the experimental fitting of a Chapelon "Kylchap" exhaust system to an existing L.N.E.R. 4-4-0 "Derbyshire". In 1930 Chapelon visited England and rode the footplate of "Derbyshire". Unfortunately, Chapelon's plans had not been well followed and the system did not work as well as it ought. 

This was far from being their only collaboration. The conventional steam locomotive has a "fire tube boiler" that is, it is pierced with tubes which take the heat from the firebox through the surrounding water to the smokebox and exhaust through the chimney. The steam generated gathers atop the boiler in the steam dome and travels from there, via the valves, into the cylinders and then out through the valves to the exhaust, creating a draught which draws the heat from the firebox through the tubes. The faster the locomotive goes, the stronger the draught, the hotter the boiler and the more steam.It is a real demonstration of a virtuous circle. But in the mid-1920s Gresley began to consider the concept of a water tube boiler such as used in marine applications. This would have been the first variation from the essential principles formulated by George Stephenson in his splendid "ROCKET" in 1829. The motivation for considering this radical change was to obtain marked economies in fuel consumption which, in his latest high-speed trains was becoming a serious concern. 

                                                  Andre Chapelon (1892-1978)

Completed at the end of 1929, No.10000, as it was designated, was a 4-6-4 with a water tube boiler operating at 450 lbs psi. It had 6'8" driving wheels. Its unusual appearance gained it the nickname "the galloping sausage" from the engine crews. After running 70,000 miles it was brought into the workshops for a major overhaul. It seems that not a great deal could be said in its favour. Gresley consulted Chapelon whose reputation for improving locomotives was legendary. Chapelon was interested in the challenge. He recommended some highly technical changes related to superheating All of Chapelon's recommendations were followed, but No.10000 never did live up to expectations. In 1937 No.10000 was fitted with a conventional boiler and streamlined in the manner of the A4s.  George Stephenson RULES!

Judging by the photograph - and there are few of them on Google Images - M.Chapelon was not the sort of person to suffer fools gladly. Perhaps this offers a clue as to why his superiors were so determined to frustrate his brilliance.

                                                              S.N.C.F. No. 242. A. 1.

The finest example of Chapelon's genius is shown in the magnificent  SNCF (Societe Nationale Chemin de Fer - the French nationalised Railways) 4-8-4  No. 242.A.1 completed in 1946.It has been described as " the most outstanding steam locomotive that ever ran upon rails".(Col. H.C.B. Rogers O.B.E. in Express Steam Locomotive Development in Great Britain and France p 105) It produced 4,000 h.p. continually at the Tender drawbar at speeds from 50 to 75 mph.Even at low cut-offs it produced 3,800 h.p.

Books aplenty have been written about the achievements of these great locomotives and their designers. How different from our own times, those in the not so distant past, have become.