The southern section between Schwerte and Iserlohn is a single-track non-electrified branch line, with a passing loop at Kalthof.

Iserlohn is therefore formally not a Bahnhof (station, which under German regulations must have at least one set of points) but instead a Haltepunkt (halt) on two lines.

After Iserlohn had been connected by rail to Letmathe in 1864, the chamber of commerce and industry campaigned in 1882 for the construction of a railway to the north towards Schwerte.

The construction of the railway was relatively expensive; 200,000 cubic metres of limestone were blasted just for a cutting in Iserlohn, where numerous fossils were found.

[2] The opening ceremony took place on 30 September 1910, coinciding with the last stagecoach ride from Schwerte to Iserlohn, the day after scheduled traffic commenced.

Sidings are still present in Kalthof (for Kettenwerk Thiele) and Hennen for the occasional transport of RWE transformers to the substation in Sümmern.

In the opposite direction the uncoupling of trains in Schwerte takes just three minutes and no specific period is required for stopping at Kalthof.