The topography of the Black Forest posed many engineering challenges in constructing the line, which has a total of 21 bridges longer than 20 m, most of which cross the Nagold or the road running parallel to it, Bundesstraße 463; and also 10 tunnels, of which the Hochdorf Tunnel between Gündringen und Hochdorf is both the longest and the highest in altitude.

The main reasons for planning such a line were: first, to create a route running north–south to Switzerland to rival the Baden Mainline between Mannheim and Basel, particularly since there was then no link between the Baden Station and the Central Station in Basel;[3] and secondly, the section between Calw and Horb, together with the planned Württemberg Black Forest Railway between Stuttgart and Calw, was to make up a new north–south mainline to replace the Upper Neckar Railway opened in 1864.

(A direct southwards connection from Stuttgart crossing the Gäu plateau was not initially undertaken because of the topographic problems).

In the years 1868–1872 a total of 4 laws were passed intended to ensure the funds for the construction of the Nagold Valley Railway.

[4] In addition, in 1870–71 the Franco-Prussian War delayed the construction work which was being carried out for the Royal Württemberg State Railways.

[3] The section of the line between Pforzheim and Brötzingen began service on 11 June 1868 as part of the Enz Valley Railway.

[5] Next, the Calw–Nagold section was built as part of the Württemberg Black Forest Railway originating in Stuttgart and opened on 20 June 1872.

[6] On 1 June 1874, under the direction of Construction Supervisor Carl Julius Abel, the Brötzingen–Calw and Nagold–Horb sections were added, with which the entire Nagold Valley Railway was open to traffic.

Between Calw and Horb, long-distance trains from Stuttgart also ran on the Württemberg Black Forest Railway to Singen and from there to Lake Constance or Schaffhausen.

In 1933, the Eutingen station was moved to its present location, about 3 kilometres (1.9 mi) from the centre of the town and not on the Nagold Valley Railway.

In the years which followed, numerous halts were closed as not economically viable; in some cases—for example Grunbach-Salmbach and Talmühle—their distance from large population centres was decisive.

For almost two decades longer, it served as a parking and layover location for rolling stock; finally in the 1970s it was abandoned and demolished.

Whereas previously the Enz and Nagold lines were two independent single tracks, the arrangement of the rails has now been changed so that the shared stretch to Pforzheim-Brötzingen is now dual-track and can be used by both.