Around 1950, André Chapelon developed two modern locomotive types with the 2-8-4 and 4-8-4 wheel arrangements for several Brazilian railway companies. While the machine shown here was designated 142N, the larger one was designated 242N. The 142N was developed for a maximum axle load of around ten tonnes and was designed to burn lignite or wood. It was used in mixed service.

Despite the meter gauge, the locomotives were all modern in design. In order to achieve enough power with the fuels used, they had a large firebox with thermic syphons. The superheater could reach temperatures of up to 380°C. Depending on the operator, different tenders were used, some of which had six axles.

The 66 locomotives were built by an export consortium called “GELSA”, which in this case involved Fives-Lille, Schneider-Creusot and Cail. In reality, it turned out that the curves with radii down to 50 meters were narrower than expected, for which the locomotives were not really suitable. That's why they were rather unpopular with the crews, who called them “too modern”. Instead, the old British locomotives were often preferred.