[1] This network unified existing regional transport in Bremen as well as surrounding cities, including Bremerhaven, Delmenhorst, Twistringen, Nordenham, Oldenburg, and Verden an der Aller.

The network lies completely within the area of the Verkehrsverbund Bremen/Niedersachsen (VBN; Bremen/Lower Saxony Transport Association), whose tariff structure applies.

Running parallel to the Weser River, it connects the entire urban area of Bremen with the southeastern suburban axis in Verden County.

The line was fully electrified in summer 2011, enabling more efficient operations with modern electric multiple units (EMUs) from December that year.

The rolling stock includes 3- and 5-car Coradia Continental units, occasionally coupled to form double sets during peak times.

Future developments include a new interchange at Bremen-Föhrenstraße to streamline connections with the RS 1 and Bremen's tram network.

The RS 4 line ensures robust connectivity between Nordenham and Bremen Hauptbahnhof, serving key towns along the Unterweser.

Externally, the train sets will be painted in Transdev colors: a white car body, blue roof and underframe, and red doors.