On 11 August 1856, the first section of the Nassau Rhine Railway (Nassauische Rheinbahn) was opened from Wiesbaden to Rüdesheim.

From 1862 to 1900 the Bingerbrück–Rüdesheim train ferry operated between Bingerbrück and Rüdesheim, connecting the East Rhine lines and the Nahe Valley Railway.

Finally in 1860 an agreement between both states was concluded, which allowed Prussia to build the Sieg line.

In return Prussia agreed to build the Pfaffendorf Bridge, which connected the line near Niederlahnstein with the West Rhine Railway (Linke Rheinstrecke) in Koblenz finished the year before.

As a result of the Austro-Prussian War of 1866, Nassau became part of Prussia, changing the situation in the Rhine completely.

The Rhenish Railway Company (Rheinische Eisenbahn-Gesellschaft) now had an interest in completing the East Rhine line, and soon received a concession for it.

Gustav von Mevissen, president of the Rhenish Railway, preferred a route via Troisdorf and Opladen to Essen.

Emil Langen, board member of the Rhenish Railway and director of Friedrich-Wilhelms Ironworks in Troisdorf (now the location of the suburb and station of Troisdorf-Friedrich-Wilhelms-Hütte), finally implemented a change in the planned route north of Beuel.

The new route went northeast from Beuel, crossing the Sieg river at Menden (now part of Sankt Augustin).

A station would be built at the Friedrich-Wilhelms works and the line would then turn southeast to parallel the Sieg Railway to Siegburg.

As a result, the building of the Sieg bridge was accelerated with extra workers, starting in the late summer of 1870.

With the opening of the Cologne-Frankfurt high-speed rail line at the end of 2002, Troisdorf station was completely rebuilt and the connections from the East Rhine railway towards Siegburg were removed.

When there are line closures on the left side, the long-distance trains are diverted to the East Rhine route.

The RB 27 operates between Porz and Koblenz, crossing from the north via the Urmitz Bridge.

Until 2010, the southern section was served by the Loreley-Bahn (RB 10) and the Loreley-Express (RE 10) services, using electric class 143 or 110 locomotives and 4-5 coaches every one or two hours.

Because of the renewal of track on the line in 2010 and the good acceleration of the FLIRT sets, the travel time is only slightly longer than that of the former RE 10 service, which did not stop at each station.

Unkel, Rheinbrohl, Rüdesheim, Hattenheim and Oestrich-Winkel stations would be largely abandoned in connection with the installation of electronic interlockings on the line.

A simulation and an operational test in the course of the Netz 21 (network 21) strategy had shown at the end of 1998 that with new, fast rolling stock for regional services and alternating stops, the top speed on the Wiesbaden–Neuwied section could be raised from 50 to 80 km/h and that several overtaking loops, 67 sets of points and 10 km of track could be dispensed with.

The EBA has also asked DB Netz to provide more overtaking tracks in the stations of Niederdollendorf, Unkel, Rheinbrohl, Bad Hönningen, Hattenheim and Oestrich-Winkel, some of which were illegally withdrawn from railway operations.

[4] The construction of new stations is planned in Bendorf (at the Rheinstraße level crossing) and in Koblenz-Horchheim (at the Alte Heerstraße overbridge).