Contemporary sources described the line as 12.051 Prussian miles (each 7,532.5 metres) long with a projected construction cost of 5.6 million thalers.

At the end of 1859 the first railway reached Trier, although passengers had to use a horse-drawn carriage from Ponten (a district of Besseringen) over the mountain to Mettlach, since the tunnel was not yet complete.

The greater part of the Saar line was controlled by the newly created French administration of the Saarland.

It was proposed in the 1950s to electrify the lines of the Saar with the modern French electrification system of 25 kV, 50 Hz.

The D-trains ran from Saarbrücken and Trier over the Eifel Railway via Gerolstein or over the Moselle line via Koblenz to Cologne.

From 1991, there were D-train services at two-hour intervals connecting Saarbrücken, Koblenz, Cologne, Münster, Bremen and Cuxhaven, with a section of these trains running to Greifswald.

Regional services has always played a large role on the Saar line, with trains between Saarbrücken and Saarhölzbach being denser than on the northern section towards Trier.

This was an hourly service from Saarhölzbach (some starting in Trier) via Merzig, Saarlouis, Völklingen and Saarbrücken to Homburg.

This project failed because of technical problems, so that RE services continue to run between Saarbrücken and Koblenz (Mosel-Saar-Express) with double-deck carriages.

In addition, RB line 71 services run from Trier via Merzig, Dillingen, Saarlouis, Saarbrücken, St. Ingbert, to Homburg.