After the purchase of the 4-6-0T tank locomotives with the numbers 51 to 65, the Paris belt railway needed even more powerful locomotives that were primarily intended to pull freight trains. The requirements stipulated that freight trains weighing 550 tonnes should be pulled on a gradient of one percent and 430 tonnes at 1.5 percent. At times of high passenger traffic volumes, additional passenger trains were to be pulled.

This time again tank locomotives with a front bogie and without trailing axles were ordered. The five locomotives therefore had a 4-8-0T wheel arrangement and a four-cylinder compound engine. While this was still implemented in a tandem arrangement on the locomotives with numbers 51 to 65, the design customary in France according to De Glehn was used here. The high-pressure cylinders were on the outside at the height of the rear axle of the bogie and drove the second coupled wheel set, while the low-pressure cylinders were inside the bogie and drove the first coupled wheel set.

Since all the cylinders were inclined and mounted higher up and the water tanks started behind the bogie, the easy accessibility of the cylinders for maintenance was ensured. The leading bogie made it possible to move passenger trains at 70 km/h without sacrificing smooth running. The ability of the coupled axles to negotiate curves was realized without movable axles by weakening the wheel flanges of the second and third axles.