The Lahn-Eifel-Bahn is a rail passenger service in the German states of Rhineland-Palatinate and Hesse that runs as the RB 23 from Limburg an der Lahn via Koblenz and Andernach to Mayen, as RE 25 from Gießen via Limburg to Koblenz and as RB 38 from Andernach via Mayen to Kaisersesch.

[2] The contract to operate the Lahn-Eifel-Bahn was awarded at part of Lot 1 of the Eifel-Westerwald-Sieg diesel network to DB Regio Südwest.

From Mondays to Fridays, the service is reinforced in the holiday season by journeys at 5:15, 6:15, 6:28, 7:15 and 13:15 from Limburg.

Due to problems with the platform occupancy in Koblenz Hauptbahnhof, it was not possible until December 2016 for all the trains of the Lahntal railway to continue to Andernach.

Due to school traffic, the daily service from Koblenz at 12:52 also ends in Andernach.

From Mondays to Fridays, the service is changed in the holiday season with journeys starting at 13:39, 16:36, 17:36 and 18:37 from Koblenz Hauptbahnhof.

In Gießen, it connects with the HLB service (RE 98/99, Main-Sieg-Express) towards Frankfurt, Siegen and Marburg.

Before the timetable change in December 2014, the Lahntalexpress was operated with class 612 sets with active tilting.

Although they no longer stop in Eschhofen, trains depart Koblenz Hauptbahnhof six minutes earlier, which means there is less time available for transfers.

Before the timetable change, rolling stock of class 640 and 648 operated on the network of the DreiLänderBahn and were stationed in Siegen.

Between Kaisersesch and Diez the fares of the Verkehrsverbund Rhein-Mosel (Rhine-Mosel Transport Association, VRM) apply.