Since 2022, the line between Fröndenberg and Unna has been closed for the foreseeable future due to damage to the railway embankment caused by badgers.

[2] The next section from Unna to Unna-Königsborn was a joint project with the Royal Railway Division of Essen and built in just over a year.

On 24 July 2022, damage to the railway embankment near Frömern was discovered that was caused by badgers, leading to the line between Unna and Fröndenberg being closed.

[8] The fact that the affected section of the route runs through a bird sanctuary and part of it through a nature reserve complicates the necessary work because of the permits or approvals required there.

It is served only by the Hönnetal-Bahn (RB 54), which continues over the Letmathe–Fröndenberg line via Menden and the Hönne Valley Railway to Neuenrade at 60-minute intervals.

[11] In 1972 a regular interval regional service was established from Unna via Unna-Königsborn, Dortmund Stadthaus and Dortmund-Dorstfeld to Dortmund-Marten Süd, which was extended in 1983 to Dortmund-Lütgendortmund.