The Saarbrücken–Trier railway, known in German as the Saarstrecke (literally the "Saar line") in the German states of Rhineland-Palatinate and Saarland. It connects Saarbrücken and Trier. It was opened in 1858 and 1860 and is one of the oldest railways in Germany.
From Saarbrücken the Saar line was opened along the Saar Valley to Merzig on 16 December 1858 and to Trier West on the left bank of the Moselle on 26 May 1860. The track stays on the right bank of the Saar and follows its many loops; as a result some of its 99 curves have very tight radii. Only one of the Saar loops, between Mettlach and Besseringen, is shortened by a tunnel.
From Trier the line continues as the Eifel Railway to Cologne and Mosel line to Koblenz. The line was built by the Royal Administration of the Saarbrücken Railway (Königliche Direction der Saarbrücker Eisenbahn), the first railway owned and operated by the Prussian government.
The purpose of the 88 km long route was to connect the industries of Trier, Mettlach (pottery), Völklingen (mining), Saarbrücken and the Saar region (mining and related industries) to the Ruhr and the North Sea ports. 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.