The PLM operated some main lines on which important express trains with high passenger numbers had to be hauled. One of these was the north-south connection from Calais to the Riviera, on which the “Train Bleu” ran with many passengers from Great Britain. Since the Pacifics were not sufficient there, one of the first Mountain locomotives in Europe was developed in 1925 with the 241 A 1. The requirements included that they should be able to haul 600-tonne express trains at 110 km/h on the level and at 75 to 80 km/h on the line between Laroche and Dijon with gradients of 0.4 to 0.8 percent.