New-build line Wendlingen – Ulm

The Stuttgart – Ulm railway project is part of the European east-west Main Line from Paris to Budapest. It is divided into the two major projects "S21 – restructuring the Stuttgart rail node" with the construction of the new main station underground, and "NBL – the new-build Wendlingen – Ulm line".  With the configuration of the main station as a through station and the connection to the European high-speed network, the travel times in regional and mainline services will be shortened significantly.

Several tunnels along the new line are built with Herrenknecht tunnelling technology. A total of four tunnel boring machines dig through the ground along the new train line for the projects Filder Tunnel, Bossler Tunnel and Albvorland Tunnel. As a result of the railway project, travel times between Stuttgart and Ulm will be almost halved. Around ten million passengers per year will benefit from the project.

Project Facts

  • Almost 50 km of tunnelling for the entire project
  • Disassembly of a Ø 10.82 m Multi-mode TBM in a 9.6 m tunnel
  • Best performances of up to 214 m of tunneling per week
  • H+E Logistik, VMT, Herrenknecht Formwork, MSD and Global Tunnelling Experts provide support with additional equipment and personnel

The machine is the best there is on the market.

Robert Pechhacker, Site Manager, Porr Bau GmbH

Filder Tunnel

The Filder Tunnel is the longest on the new line between Stuttgart and Ulm, which will link the new central railway station with the Filder Plain and the airport. For the twin-tube 9.5 kilometer long tunnel Herrenknecht is supplying a convertible Multi-mode TBM with a shield diameter of 10.82 meters. In the upper section of the Filder Tunnel, it works in closed mode with screw conveyor while the lower section involves open mode with conveyor belt discharge.

Challenging geology

This is because of the varying layers of rock: the machine has to penetrate sandstone with marls and clays and nodular marl as well as unleached gypsum keuper. It overcomes an altitude difference of 155 meters with a gradient of up to 2.5 percent. Only in about half of the tunnel, in the geological transition zone, the machine will not be used. There miners will remove the material from inside the mountain using diggers and loosening blasting. Due to these complex project requirements, initially no mechanized tunnelling was planned for the Filder Tunnel. However, the particularly flexible and convertible Multi-mode TBM machine type from Herrenknecht has convinced the client of the advantages of mechanized tunnelling over a large part of the tunnel route.

After the traditional christening of the machine with the name of SUSE (abbreviation of the German for "Stuttgart-Ulm reached faster") in July 2014 and the start of the advance toward the main station in November 2014, in March 2015 the TBM reached the 1,000 meter mark. After a good 4 kilometers of tunnelling as far as the beginning of the geological transition zone, in November 2015 the first phase of construction in the eastern tube was successfully completed. The machine was then disassembled in the tunnel. It is being refurbished in readiness for the second of a total of four advances in the parallel western tube taking it back toward the main station. 

Precise to the millimeter: underground TBM disassembly

In order to realize the complex construction process – including TBM disassembly in the bored tunnel – quickly and safely, close cooperation between all project partners was required from the outset. With a shield diameter of 10.82 meters and an inside diameter of the tunnel of 9.6 meters, the disassembly and transport back to the launch portal were only possible in the specified time frame because all mechanical engineering and logistical requirements were precisely planned in advance and then implemented on the jobsite. 

The Multi-mode TBM tackled the second shield drive from the Filder portal to Stuttgart main station in June 2016. One year later, in July 2017, the machine arrived at the transition zone in the western tube, through which it was pulled through subsequently. From November 2017 until July 2018 SUSE successfully completed the third drive of the Filder Tunnel and reached the cavern, where the machine will be turned around by 180° for the final drive in the eastern tube back to the Filder Plane. The last tunnel section is located in heterogeneous rock strata and overcomes a total height difference of 155 meters with a slope of up to 2.5 percent. Final breakthrough of SUSE was celebrated in September 2019.

Bossler Tunnel

Under the Swabian Alb toward Ulm, with overburdens of up to 250 meters a Herrenknecht EPB Shield (diameter 11.34 meters) is driving the 8.8 kilometer long twin-tube Bossler Tunnel. It is the railway tunnel with the largest diameter excavated in Germany to date using mechanized tunnelling technology and is expected to go into operation in 2022.

From Ulm to Stuttgart in no time

At the launch portal near Aichelberg the christening of tunnel and TBM ("Käthchen" or Kate) was held in November 2014, in April 2015 the giant "worm" started on its way. By June 2015 already the thousandth meter of tunnel had been bored and lined with concrete segments produced in moulds from Herrenknecht Formwork in a purpose-built factory close to the Aichelberg tunnel portal. A total of 60,000 segments were installed in the Bossler Tunnel.

Tunnelling progressed so quickly that the decision was made to drive additional sections with the TBM that were originally planned to be built using conventional methods. As early as beginning of November 2016, the proud miners celebrated the final breakthrough after 8.8 kilometers in the eastern tunnel. In April 2017 "Käthchen" started the excavation of the western tunnel that was successfully concluded in June 2018 after best weekly performances of up to 214 meters. The TBM from Herrenknecht excavated nearly 7.8 kilometers in the first tube and even 8.8 kilometers in the second one – which is almost the entire tunnel distance.

Albvorland Tunnel

After the Filder Tunnel and the Bossler Tunnel, the approximately 8 kilometer long Albvorland Tunnel is the third tunnel structure on the new-build line between Stuttgart and Ulm for which Herrenknecht is supplying mechanized tunnelling technology. For the first time, the contractor is using two tunnel boring machines in parallel, each of which will excavate nearly 8 kilometers of single-track tunnel tube from east to west. The tunnelling experience gained from the neighboring lots of the Filder and Bossler tunnels helped, among other things, to optimize the design of the cutting wheels for the Albvorland tunnelling machines. On the other hand, it was necessary to take the peculiarities of the assembly and start-up situation at the Albvorland Tunnel into account for the shield and back-up design.

After the two machines designed as EPB Shields (Ø 10,820 mm) had successfully completed their acceptance by the customer at the Schwanau plant in March 2017, a crew of 20 specialized Herrenknecht experts carried out the assembly at the east portal near Kirchheim unter Teck. Here they followed a sophisticated plan by which the modules were gradually assembled in the site set-up area and lowered into the narrow launch shaft.

From January 2018 to the beginning of August 2019, the Herrenknecht EPB Shield named Sibylle excavated 7.5 kilometers of the north tunnel of the Albvorland Tunnel with a peak performance of up to 200 meters per week. WANDA in the south tunnel covered 7.5 kilometers between November 2017 and the breakthrough in October 2019 at up to 186 meters per week. 

Stuttgart – Ulm railway project

Column 0 Column 1
Tunnelling Length 48,506 m
Soft ground: 
Lower Jurassic (marl, claystone and limestone layers), White Jurassic, Brown Jurassic, opalinus clay

Heterogeneous ground: 
Liassic & Rhaetian, nodular marl, sandstone with marls and clay, unleached gypsum keuper
Client Deutsche Bahn AG
Filder Tunnel ARGE ATCOST21 / Bossler Tunnel ARGE ATA; Porr Bau GmbH Tunnelbau, G. Hinteregger & Söhne Baugesellschaft m.b.H., Östu-Stettin Hoch-und Tiefbau GmbH, Swietelsky Baugesellschaft m.b.H. 

Implenia Construction GmbH 
Machine Data
1x EPB Shield:
Diameter: 11,340 mm
Lining method: Segmental lining
Cutterhead power: 4,550 kW
Torque: 20,086 kNm

1x Multi-mode TBM:
Diameter: 10,830 mm
Lining methodSegmental lining
Cutterhead power: 4,200 kW
Torque: 23,838 kNm

2x EPB Shield:
Diameter: 10,820 mm
Lining methodSegmental lining
Cutterhead power: 4,400 kW
Torque: 15,451 kNm

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Steffen Dubé President and General Manager Herrenknecht Tunnelling Systems USA Inc.
Gerhard Goisser Commercial Manager Herrenknecht Tunnelling Systems USA, Inc.

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Steffen Dubé President and General Manager Herrenknecht Tunnelling Systems USA Inc.
Gerhard Goisser Commercial Manager Herrenknecht Tunnelling Systems USA, Inc.