The Rhein-Erft-Express is a Regional-Express service in the German states of North Rhine-Westphalia and Rhineland-Palatinate. It is numbered as line RE 8 and connects the cities of Mönchengladbach, Cologne, Bonn and Koblenz with each other and their surroundings, running hourly. It is complemented by a Regionalbahn stopping service, the Rhein-Erft-Bahn, running also between Mönchengladbach Hauptbahnhof and Koblenz Hauptbahnhof. On weekends it stops at some additional stations between Cologne Hbf and Koblenz Hbf. It is operated by DB Regio with Alstom Coradia Continental EMUs.

Mönchengladbach Hauptbahnhof is a railway station in the city of Mönchengladbach in western Germany.