In the 1930s, the Nord was planning a new express locomotive that, due to its size, should achieve lower operating costs with longer trains and should also ideally be suitable for the speed range between 160 and 200 km/h.

In order to be able to determine the ideal cylinder arrangement, Marc de Caso developed the 232 R with a simple three-cylinder engine and the 232 S with a four-cylinder compound engine. Due to the founding of the SNCF, the program was postponed and the three 232 R were therefore only delivered in 1940.

The wheel arrangement chosen was 4-6-4 since it was possible to use a boiler of the same size as a 4-8-2 and at the same time take over large chassis parts from a 4-6-2 and replace the trailing axle with a bogie. A streamlined fairing was necessary in order to be able to reach the required speeds.

Locomotive Magazine, January 1948

The boiler was operated at a relatively high pressure of 20 bar. Otherwise, the locomotives had a Lemaître blast pipe, an ACFI feed water heater and modern injectors. The tender was basically designed for 38 m³ of water, but could only hold 36 m³ with the built-in stoker. On an incline of 0.4 percent, they could tow 685 tonnes at 113.5 km/h, which corresponded to an output at the drawbar of 2,615 hp. 

The tractive effort calculated from the cylinders is more of a theoretical value that could only hardly be achieved under real conditions. The practical quotient of adhesive weight and tractive effort for three-cylinder locomotives is usually given as 3.5, but it is 2.65 here. Thus, depending on the condition of the rails, there will have been a strong tendency to slip. If you take the value 3.5 as a basis, you get a realistic pulling force of 193 kN or 43,400 pounds. 

The three locomotives were tested on the Paris-Lille route in front of regular trains. Due to the war, their power could not be fully exploited and they were only approved for 140 km/h. Two locomotives were retired in 1958 and the third in 1961.

In addition to the 232 R with a simple three-cylinder engine, the Nord had the 232 S developed with a four-cylinder compound engine. It was therefore also used to test powerful express locomotives for the highest speed range. Due to the founding of the SNCF, the program was postponed and the four 232 S were therefore only delivered in 1941. They had streamlined bodywork that looked very similar to the 232 R. The similar 232 U 1, ordered at the same time, was not completed until 1949.

The Zara valves of the four cylinders were controlled by a rotating Dabeg camshaft control. Otherwise, the locomotives had a Lemaître blast pipe, an ACFI feed water heater and modern injectors. The boiler worked with a pressure of 20 bars. The tender was basically designed for 38 m³ of water, but could only hold 36 m³ with the built-in stoker. On a gradient of 0.5 percent, they could pull 595 tonnes at 113 km/h, which corresponded to an output of 3,400 hp. 

The four locomotives were tested on two different lines in front of regular trains. Due to the war, the performance of the locomotives could not be fully exploited and they were only approved for 140 km/h. Since the valve gear had problems, it had to be replaced in 1954 with another one with an oscillating camshaft. Their service life ended in 1961 and the SNCF did not order any more express locomotives with a 4-6-4 wheel arrangement, as locomotives with four coupled axles were now used for the heaviest trains.

When the French State Railways were already planning the complete conversion to electric and diesel locomotives, André Chapelon designed an express steam locomotive with an output of 4,000 hp at the drawbar. As a basis, he used the Est 241-101, which had not made it into series production, and modified it accordingly. He converted the simple three-cylinder engine into a compound engine and provided the locomotive with optimized steam pipes and a Kylchap exhaust system.

The result was the most powerful steam locomotive ever built in Europe, producing between 5,230 and 5,430 hp (3,900 and 4,048 kW), depending on the source. While the original locomotive only had 2,550 hp on the drawbar, over 4,000 hp were now achieved and express trains heavier than 1,000 tonnes could be pulled. Up to 158 km/h were reached on test runs and approval was given for 130 km/h. The machine was put into service in 1951, but was only used sporadically due to the decision to electrify the network and was scrapped in 1961.

Although the electrification of the French main lines was already foreseeable shortly after the end of the Second World War, particularly powerful steam locomotives were needed for the transitional period. Since express trains with up to 20 four-axle coaches had to be hauled on mountainous main routes, an output of around 4,000 hp was required. The choice fell on a locomotive with a 4-8-2 wheel arrangement, which was also called the “extended Pacific” in France. The 241 P developed in this way was the last steam locomotive in Europe with this wheel arrangement.

The 241 C of the PLM from the year 1930, which had only been built once, was used as the basis. In the De Glehn four-cylinder compound powerplant, the high-pressure cylinders were located within the frame between the first and second coupled axle and drove the third coupled axle. The low-pressure cylinders were level with the middle of the bogie and drove the second coupled axle. André Chapelon was involved in optimizing the steam paths in the boiler and powerplant, but did not have the opportunity to redesign the design in depth. In addition, a double, cloverleaf-shaped blowpipe based on the PLM design and a mechanical stoker were installed.

241 P 1 on a post card of 1950

Compared to the 241 C, the 241 P achieved about 20 percent more power. While the predecessor did not make it into series production, a total of 35 examples of the 241 P were built up to 1952. As standard they received a tender with 34 cubic meters of water and twelve tonnes of coal, but alternatively tenders with 36 cubic meters of water and only nine tonnes of coal were also used.

The engines first came to the Sud-Est and Nord regions. After the most important main lines there were electrified, some were moved to other lines within the regions and others were moved to the Est and Ouest regions. In the 1960s, they were able to prove their power one last time when they had to stand in alone to replace broken A1AA1A 68000 diesel locomotives, which were otherwise used double-headed.

In January 1969, 17 of the 35 pieces were still in use. In that year, the number of remaining engines decreased rapidly, so that the last regular operations took place on September 28, 1969. Four engines have been preserved, with number 17 being the only operational one to date, making it the most powerful operational steam engine in Europe. Number 9 could also become operational again in the future.

141 R 1126 in July 2006 at Toulouse-Matabiau station

ignis

Since there was a major shortage of locomotives after the liberation of France in World War II and the North American manufacturers still had capacities, SNCF ordered a total of 1,340 Mikados for freight and passenger service. The actual design came from Baldwin and was based on the USRA Light Mikado, which was made a little lighter and adapted to the French loading gauge. The locomotives were easier to maintain than the French ones, being built after American principles, and quickly spread across the country. The coal-fired locomotives were almost exclusively used in front of freight trains and the oil-fired ones could also often be found in front of passenger trains. They remained in service until 1974, when all steam operations in France ceased.