Due to the need of a simple to operate and solid locomotive, the Chemins de Fer de l'État even went to choose the pressure of the boiler (or timbre in French).

The pressure was 12 kp/cm2 or 12 hectopièzes (old units of measurement, 1.2 MPa in modern units), this enabled the machine to develop an output of 1,540 hp (1,150 kW) at 60 km/h and 830 hp (620 kW) at 100 km/h.

From 1932 the timbre was increased to 14 kp/m2 to obtain a power of 1,700 hp (1,300 kW) at 60 km/h and 1,160 hp (870 kW) at 100 km/h; locomotives were recoded from "B" to "C" as this work was done.

There it received new Renaud type valves, saving 9.8% coal.

One locomotive has been preserved: 141.C.100 (and tender 22.B.609) are in working order and are listed as a Monument historique.