French State Railway 232 S

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.