The B Line is the second line in the network of the Frankfurt U-Bahn, running in a west–east direction from the central railway station (Hauptbahnhof) through the old town to Konstablerwache, where it splits into two branches to Bornheim (served by the U4) and Preungesheim (served by the U5).
Route
The B line can be divided into three sections: the trunk line used by the U4 and U5 between the central railway station (Frankfurt Hauptbahnhof) and Konstablerwache and the two branches which the line splits into at its eastern end.
Konstablerwache - Hauptbahnhof
Below the subterranean shopping arcade under the station forecourt is the four-track underground station at Hauptbahnhof, which was built as a shared station for the B and D lines. It has two island platforms, which according to long-term planning are to be used for cross-platform interchange between the north–south D line and the east–west B line. At present, however, only the eastern branch of the B line and the northern branch of the D line exist. Since the commissioning of the D line extension of the U4 to Bockenheimer Warte, U4 trains to Bockenheim and terminating U5 trains use one of the inner tracks, starting U5 trains use the other inner track, and the outer western track is used by the U4 to Bornheim. The eastern outer track is intended for the unbuilt southbound D line and has never been put into service. The central station is the most important transport hub in the region and offers connections to S-Bahn trains (in an underground station below the U-Bahn), trams, city and regional buses, and regional and long-distance train services.
After leaving the southern end of the station the tunnel turns left to travel under Gutleutstraße to Willy-Brandt-Platz. In 1974 this station became the first transfer station of the Frankfurt U-Bahn, where the B Line crosses the A Line. The B Line station lies below that of the A Line and both lines have side platforms. The station is located in the Frankfurt financial district on New Mainzer Straße. The Eurotower of the European Central Bank did have a direct access, but the management of the ECB has let it close.
The route continues through the Altstadt, first under Weißfrauenstraße, then Münzgasse and Limpurgergasse to reach the Römerberg, the central square of the old town.The station, called Dom / Römer, lies deep below the oldest settlement in Frankfurt. It has a central platform and an intermediate level decorated with carved stones from nearby buildings destroyed by air raids in 1944. Probably the longest escalators of Frankfurt's rapid transit stations lead to the eastern exit at the foot of the western tower of Frankfurt Cathedral.
Beyond Dom / Römer station, the route runs under the cathedral square and Kannengießergasse to Fahrgasse, which it crosses before swinging in a wide arc under two blocks and the Dominican monastery in a northerly direction to follow the course of the Kurt-Schumacher-Straße and reach Konstablerwache. Below the pedestrianised square, there is a large underground rapid-transit railway station. In the second underground level there is a three-track station for the B line. Perpendicular to this and one level lower is a four-track station for the U-Bahn C Line and the S-Bahn. Trains on the B line use two tracks in the direction of the central railway station, because the branches from Bornheim (U4) and Preungesheim (U5) meet here, but in the opposite direction both services use the same track as the tunnel only splits after leaving the station.
Konstablerwache - Preungesheim
From Konstablerwache the branch to Preungesheim heads north under Konrad-Adenauer-Straße to the Friedberger Tor and then emerges from its tunnel in the Wallanlagen park. The Wallanlagen are actually protected from any development by the Wallservitut of 1827, so the route is a violation of the most famous Frankfurt building regulation. From the mouth of the tunnel the route has around 1200m of on-street running along Eckenheimer Landstraße, shared with other traffic. This was originally intended as a temporary step in the conversion of this route from tram to U-Bahn operation.
From the junction with Oeder Weg, Eckenheimer Landstraße becomes wider and the route has reserved tracks in the central reservation. At Marbachweg the line turns east and then north into Gießener Straße. Between 1974 and 1978 the station at Gießener Straße was the northern terminus of the line, until the continuation north along Gießener Straße opened on 6 March 1978, replacing a tram line in the parallel Homburger Landstraße. Unlike this, today's route no longer runs directly to the center of Preungesheim, but to a residential area characterised by its 1950s buildings. By the station at Sigmund-Freud-Straße there are also 1960s residential skyscrapers. The three-track terminus at Preungesheim is located at the junction of Gießener road and Homburger Landstraße, just south of the A661 motorway bridge.
Barrier-free platforms
When the Preungesheim branch originally opened the stations had low-level platforms or access from street level. From 2013 to 2016, high-level platforms were built at the above-ground stations to allow barrier-free access to the trains. In addition to the dismantling of the existing platforms and the construction of the new side platforms the renovation work included adjustments to the tracks and overhead lines and adjustments to the road and traffic management, the cycle paths, and traffic lights, which will give priority to U-Bahn trains along the route. The stations at Neuer Jüdischer Friedhof and Eckenheimer Landstraße / Marbachweg were taken out of service instead of being rebuilt. Eckenheimer Landstraße / Marbachweg will not be rebuilt because it is only around 70m away from the station at Marbachweg / Sozialzentrum. The reconstruction of Neuer Jüdischer Friedhof was planned to take place from 2018.
Intersection At the intersection, Eckenheimer Landstraße - Glauburgstraße branches off an operating route to the east. It is the remainder of the former route Eschenheimer Tor - Oeder way - Glauburgstrasse - Nordend, which was used until 1963 by the route 12, one of the main services of the Frankfurt tram network. With the beginning of the underground construction work, the route was shut down by the Oeder way and the tram service 12 moved into the Friedberger highway. The remaining stretch of the route from Eckenheimer Landstrasse to Friedberger Landstraße served as the main access road for all lines in the Eckenheim depot except the 13 and the 22, which were fed via the Marbachweg. In the rush hour this route was additionally used until the 1980s by the tram line 25 (formerly 5). It operated from Eckenheim on the Glauburgstraße to Bornheim and on to Fechenheim. Today, the route is for operational purposes only. After expanding the course towards the city center in 2002, it is only passable from and to the north. The route leads east to the intersection Friedberger Landstraße / Rohrbachstraße, where it joined in both directions to the route of the tram service 12. In the course of the expansion of the new tram service 18 to Preungesheim in 2010, the direct connection Eckenheim–Bornheim was capped and the route closes in the intersection Friedberger highway / Glauburgstraße / Rohrbachstraße only in the direction of the city center.
At the crossroads Marbachweg / Eckenheimer Landstraße branches off two further distances: from here to the north a twin-track operating line leads to the former, today only as Wagenhalle used operating yard corner home. This route used to be run by the HVZ Line 5, which was later renamed 25, as well as some sections of the timetable from lines 19 and 27.
Towards the west, the single-track section of the former tram services 13 and 22 leads over the Marbachweg to the Eschersheimer Landstraße, where it connects at the Dornbusch station to the A-line, which is also at street level. This route continued from 1963 to 1978 through the Hansaallee and the Reuterweg to the Opernplatz. That too will no longer be on scheduled service today.
Konstablerwache - Bornheim
The route from the Konstablerwache to Bornheim belongs to a second phase of construction and opened on 31 May 1980. The tunnel begins by follows Berger Straße through Nordend to Bornheim. Due to the narrow width of Berger Straße the tunnels for the two tracks were not built side by side, but one above the other and the stations at Merianplatz, Höhenstraße and Bornheim-Mitte have two single-track platforms on different levels. All three stations are simply designed with ceramic wall tiles in warm, bold colours. The station at Bornheim Mitte, located where Berger Straße crosses Saalburgstraße, is the most important public transport node in the district and provides connections to trams in Frankfurt am Main and buses.
After leaving Bornheim Mitte the tunnel leaves Berger Straße and curves north to reach Seckbacher Landstraße, where the station of the same name is located. Beyond Seckbacher Landstraße the tracks leave the tunnel and continue above ground to Depot East () and a connection to the C Line.
Services
U4
The U4 service began operation in May 1980, when the Bornheim branch of the B line opened. It was the first U-Bahn service in Frankfurt to run entirely underground, linking the central railway station to Seckbacher Landstraße in Bornheim. In 2001 the U4 was extended almost from the central railway station to Bockenheimer Warte with an intermediate station at the Frankfurt Trade Fair. This extension forms part of the incomplete D Line. In June 2008 some U4 trains were extended past Seckbacher Landstraße to Schäfflestraße on the C Line. After six months of trial operation the line was permanently extended to Enkheim in December 2008, sharing the existing ground-level tracks used by the U7 service. One U4 train every 15 minutes runs as far as Enkheim, with the others terminating at Seckbacher Landstraße.
U5
The U5 service runs from the central railway station via Konstablerwache to Preungesheim. It began operation, as the B1, on 26 May 1974 between Willy-Brandt-Platz (then called Theaterplatz) and Gießener Straße, and was extended to Preungesheim in 1977 and the central railway station in 1978 when these sections of the B Line opened. At this time the line also became known as U5.
When the tunnel to Bornheim opened in 1980 the U5 service was cut back to only run between Konstablerwache and Preungesheim. The lack of high-level platforms on the Preungesheim branch meant it was operated with type Pt trams, which were narrower than the U3 trains used on the U4 service to Bornheim and could not use the same high-level platforms on the shared underground section. Although the Transport Committee of the City Council had recognised the problem in 1977, a change to the U3 trains was rejected by the Stadtwerke on the grounds that they were already under construction. It turned out later that this did not correspond to the facts and a change of construction would have been possible. The Stadtwerke attempted in this way to prevent a mixed operation of the delay-prone street-running U5 service with the metro standard U4.
In 1998 a solution was found for the mixed operation of both vehicle types. The Pt trams were converted to type Ptb with widened sections around the doors. The Ptb trams were used by U6 and U7 services on the C Line as well as the U5, which was extended back to the central railway station. Since the rebuilding of the stations on the Preungesheim branch with high platforms, it has been possible to use U5 trains on the U5 service.
the U5 has again been shortened to only run between Konstablerwache and Preungesheim, this time due to a shortage of train drivers.
History U-Bahn in Altstadt