French Northern Railway No. 4.001 to 4.075 and 4.636 to 4.990

Over a long period from 1866 to 1891, the Nord had a total of 430 freight locomotives of basically the same type built. With the 0-8-0 wheel arrangement, they were among the most powerful models at the time of their introduction. The nickname “180 Unités” came from a French unit to measure tractive forces. Four units corresponded here, for example, to a freight car with a load of less than ten tonnes, which is pulled on the flat at 50 km/h.

The cylinders, which were quite large with a diameter of 500 mm, were already mounted outside the frame. In reality, the locomotives could pull coal trains weighing 680 tonnes on lines with a maximum gradient of 0.6 percent. At 1.2 percent, 415 tonnes could still be pulled. In later series, the boiler pressure was increased from 8.5 to 10 bars, which increased the train weights accordingly.

The locomotives built after 1879 were fitted with a boiler with a Belpaire firebox. From 1890, a driver's cab was installed ex works. Between 1907 and 1913, 108 locomotives were rebuilt into tank locomotives. Other machines from the Nord-Belge that were almost identical in construction were also rebuilt in this way and used in Belgium.

When the SNCF was founded in 1938, only two of the non-rebuilt tender locomotives were still in use. Of the 108 tank locomotives, a total of 104 were still in use. The last of these remained in use as shunting locomotives until 1962. Today only 4.853 survives, which was not converted into a tank locomotive and was used in a sugar refinery until the 1960s.