André Chapelon

updated october 30, 2013

always under heavy 

André Chapelon. October 26th, 1892 - july (22nd?), 1978. 

He was nicknamed "Le petit" - "Shorty" - by colleagues and friends. 

"The work accomplished by Chapelon, by transforming locomotives which were far from new and bringing incredible improvements to their performances, justify an opinion making him the greatest engineer in locomotives since Robert Stephenson. If it's true, that's because him alone seemed to be able to embrace the full significance of these biological interactions between the various organs of the machine and to deal with them in a scientifical manner, in such a way that he was even able to predict the extroardinary results they will gave. His locomotives reached a power to weight ratio and a thermic efficiency never sawn before with steam locomotives, and they gave no more incident in service than those who were in charge of them had wanted to."

J.T. Van Riemsdijk & K. Brown, "The pictorial history of steam power", "Steam on the railways" chapter, Octopus Books, London 1980 and Gallery Press, 1984. Retranslated from a french edition.

PLEASE NOTE: Every paragraph will become a link to a specific page in a (more or less) close future... These are only short introductions. More hours per day, please! Come back from time to time, I sometimes add a few details here.


The beginning of his engineering career:

His first creation: The KYLCHAP exhaust system,  

What was exactly his contribution and theories to compound locomotives design: Mainly the to relegate of rule-of-thumb and voodoo-inspired theories and design rules to the "cul de basse-fosse", deep holes were thrown (and quickly forgotten!) alive persons in ultimo punishment some centuries ago, in favour of the real scientific knowledge of his time and by a systematic checking of theories by the use of extensive tests of engines in real conditions and with the help of correctly used modern metering equipment such as, for example, high speed stroboscopic cameras he used to study steam flowing. Details and more by clicking HERE someday. Maybe.

His locomotives (the ones which were built, all compound):

Very innovative work on single expansion engines too:

Narrow gauge single-expansion  locomotives designed for Brazilian's railroads after he left the S.N.C.F., french nationalized railroad company:

Plans of machines for the fifties-sixties (never build, mainly because of the "All nuke", leading to "everything electrical" politic favoured by generations of our mad politicians):  Chapelon had sincerely a great admiration for industrial capacities of the United States and also for the resulting quality of U.S. engineering. Also, Timken roller bearings, cast chassis, Union Pacific type rods, mechanical firing and more yet U.S. engineering habits were parts of specifications of Chapelon's projects. Most of them were most than planned but fully designed up to execution drawings, even two set of cylinders for the 2 10 4's were cast as well as boiler parts built.

Co-designed engines (S.N.C.F. era): Although Chapelon was really affected to be compelled to collaborate to their design because the specs. of those, imposed by S.N.C.F. management was in total contradiction with thermodynamics knowledge of the time as well as with his pre-S.N.C.F. work

The scientifical and theoretical ressearches made by Chapelon , on building methods and construction practices were direct applications of the most up-to-date materials, tools, measurement and data acquisition systems. 10 years after he has been pushed away to the exit door by Mr. Louis Armand, general manager of the "Société Nationale des Calamités Ferroviaires" (tr.: National Society of Railroad Calamities) as Chapelon nicknamed it,  the S.N.C.F.'s designers in charge of very high speed electric engines projects consulted Mr. Chapelon to help them to solve heavy trackholding problems they were faced to as he had mathematically and experimentally modelled every railroad engine (single expansion 2, 3 and 4 cylinders, compound also in various cylinders configurations, electric...) behavior on the track (swinging, rolling, pitching) in the early twenties, in times where the first series of electric locomotives (Bo-Bo of the Paris Orleans for example) were nicknamed "The Railbreakers"! So he is also vastly responsible for French successes in the very high speed electric railroads domain, and of subsequent industrial business "made in France" with those.

A curiously unrecognized Chapelon's assistant Willoteaux invention: The Willoteaux's piston valve, used on the 242 A 1, 141 E 113, and a on a great number of machines designed by other french engineers. If you know application of those in other countries, please send me some infos.

Applications of Chapelon's theories and creations to other french railroad companies' locomotives:

And to locomotive of other countries by foreign designers. But why they didn't went deeper in Chapelon's way? Because it was already too late.

International opinions about the work of André Chapelon, some texts also containing interrogations and answers about the evident negation of this work made by nationalized railroads management (not to say by the French government...) leading to premature withdraw of most then to the total destruction of Chapelon's highly subversive engines against unanimous technical staff opinion.

Conclusion: I think only a very few engineers and scientists around the world - ex-eastern block people excepted - can figure out to how much non scientific or technical but administrative, hierarchical and thus human difficulties Chapelon was faced to all along his career. It's not only my opinion, it's shared here and elsewhere by everyone knowing the topic and seems thus reach the status of Historical truth. Unfortunately, it seems to be a constant of the life of engineers and researchers in France still today (3000 engineers left France for foreign countries in 1996, an official figure in constant and regular increase).



MANY MORE bibliography to come! I.S.B.N. codes available (when it exists!) on request.


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