Railway Giants: A Steam Locomotive from 1946 Outperforms Modern Electric Trains

André Chapelon, a name synonymous with dedication and creativity, brought steam locomotives to their pinnacle. Through his persistent work, he developed the most powerful steam locomotives, only halted by the limits of steam power. What was the story of this inspiring genius? We explore this in the new installment of our series on railway giants.

Changing Times

It's October 1892, and we find ourselves in Saint-Paul-en-Cornillon in southeastern France. Here, a boy named André Chapelon is born. He enters the world during one of Europe's happiest periods. It has been over 20 years since the fall of Napoleon III and his empire. The French Republic, like most of Europe, is experiencing an era of peace and prosperity unparalleled in history. Quality of life is improving, steam locomotives are speeding through the countryside, and soon, man will fly for the first time. Prosperity is evident everywhere in Europe. Few suspect that this is the calm before the storm, with two great wars and an economic crisis set to transform all this prosperity into a living hell in the 20th century.

But let us return to André in France. He begins his studies at the prestigious École Centrale Paris, excelling in mathematics and natural sciences. All indications suggest André will soon complete his studies, but circumstances intervene. The outbreak of World War I interrupts his education, and like most of his peers, André actively participates, serving as an artillery officer in the French army.

After the war ends, André returns to school in 1919, successfully graduating in 1921. He immediately joins the railway company Chemins de fer de Paris à Lyon et à la Méditerranée as a trainee in the field of rail vehicles and engines at the Lyon depot. Despite his good work, the company struggles overall, and when he receives an offer to change employers, he doesn't hesitate for long.

Time to Work

In 1924, André becomes an employee of a telephone company, quickly rising to the position of assistant director. However, this job doesn't fulfill his creative desires. It's no surprise when he changes employers again in 1925, joining the railway company Chemin de Fer de Paris à Orléans. Here, he works closely with Finnish engineer Kyösti Kylälä, designing new steam locomotives for the company. Their first creation is locomotive number 4-6-2, which, despite initial skepticism from experts, proves successful. This success continues with other locomotives bearing André's signature.

André distinguishes himself from most designers of his time. While the common practice is trial and error, André seeks to understand and comprehend his machines. He must know why some designs work better than others. To this end, he conducts numerous tests, leading to principles that make his designs unparalleled.

One of his machines' greatest strengths is their efficiency, allowing relatively small locomotives to achieve high performance. After 1929, André also begins to rebuild locomotives, including several designed by engineer Alfred de Glehn. He optimizes steam flow and improves exhaust systems, using his own invention, the Kylchap exhaust.

In addition to the locomotive's internals, André studies the wheel-rail interface, particularly the driving characteristics of steel wheels on steel rails at various speeds. His findings will be utilized years later in the development of French high-speed TGV trains.

Reaching the Pinnacle

His insights are fully realized in the extensive rebuild of the Pacific 4521 locomotive into the 4-8-0, completed in August 1932. The success of this project leads to eleven more rebuilds into locomotives numbered 4701-4712 (later 240 701 - 240 712), achieving very high performances. Many of his designs are exported to other countries, including Brazil and the USA. He also collaborates with Czechoslovak State Railways, consulting on the production of the ČSD 476.0 locomotive.

The pinnacle of his work is the 242 A1 locomotive, regarded by many experts as the zenith of steam locomotive development. Created from the Etat 4-8-2 rebuild, this locomotive incorporates many of André's improvements, including the triple Kylchap exhaust, double high-pressure valves, and Willoteaux valves on the low-pressure cylinders. Completed in 1946 with a power output of 5500 horsepower, it surpasses contemporary French electric locomotives, prompting a redesign to increase their power by another 1000 horsepower (750 kW).

For his lifelong service to the French railway, André is appointed vice president of the Stephenson Railway Society in 1971. He passes away in 1978 at the age of 85, leaving behind a legacy as a genius who brought steam locomotives to their ultimate peak. While many engineers will attempt to build on his work, his locomotives remain unsurpassed in steam power. André exhausted and perhaps even surpassed the potential of steam, leading to the decline of steam locomotives in everyday use in most countries.