It will be several years before the U5 actually reaches the Europaviertel. But an important step in the construction of the new underground tunnel has now been taken with the starting ceremony of the 80-metre-long tunnel boring machine. This imposing machine will be digging its way through Frankfurt's subsoil from September onwards. The machine was christened at a ceremony on Monday in the presence of Hesse's Minister of State for Economic Affairs, Energy, Transport and Housing Tarek Al-Wazir, Frankfurt's Lord Mayor Peter Feldmann, Frankfurt's Head of Transport Klaus Oesterling and the management of Verkehrsgesellschaft Frankfurt am Main (VGF), Stadtbahn Europaviertel Projektbaugesellschaft (SBEV) and PORR GmbH.
The tunnel boring machine was christened "Eva", which emerged from a public naming competition in 2018 and stands for "connecting the Europaviertel". The tunnel godmother whose name the tunnels will receive is journalist and "Lotto Fairy" Franziska Reichenbacher. According to old miners' tradition, the tunnel godmother is the earthly deputy of St. Barbara, the patron saint of miners and miners.
Frankfurt is one of the cities with the highest volume of commuters and Minister of State Tarek-Al-Wazir knows: "This city is the center of the dynamic Rhine-Main metropolitan region. Since 1968, the underground has developed into the backbone of public transport and it is impossible to imagine the city without it. Its efficiency must be maintained by modernizing and repairing the existing facilities and expanded by building new lines. The latter, emphatically supported by the state of Hesse and the federal government with 157 million euros, is happening in a very impressive way with the underground construction in the centre of Frankfurt."
The extension of the U5 beyond the main station will connect a growing district to the city's local transport network and thus also further revitalise it. For Lord Mayor Peter Feldmann, this is an important step towards making Frankfurt mobile in the future: "We made a landmark decision in 2012 when we decided to connect the Europaviertel to the public transport network with an efficient underground railway. After the groundbreaking ceremony in late summer 2017, the next milestone now follows with the start of drilling by the tunnel boring machine. The people who live and work here, or will do so in the future, will find a modern, fast, public transport system with the U5 extended into the Europaviertel from 2024 onwards, as they are entitled to expect from a city like Frankfurt."
During the advance, eight miners work on the machine and twelve miners of the logistics per shift. In total, the team consists of 60 miners. "With all the demands that such a large construction site means in the middle of the city, the most important thing still remains: that no one gets hurt and nothing happens to anyone during the construction work," says tunnel godmother Reichenbacher. "Therefore, 'Glück auf' to all the miners who will be building the new tunnel in the coming months at a depth of up to 25 meters underground in Frankfurt."
The construction project includes a 2.7-kilometer route with a total of four stations. In the future, the route will run from the underground "Güterplatz" station via a ramp to the surface and continue westwards on a grass track in the middle of Europa-Allee. The stations "Emser Brücke", "Europagarten" and "Wohnpark" will be built on the surface after the tunnels have been constructed.
"A public transport network with modern vehicles and stations, clever timetables and attractive services is a very important location criterion for a city and its region. Frankfurt and the Rhine-Mein region depend on a functioning public transport system, because only with it - sensibly linked with other sustainable modes of transport - can we guarantee the mobility that will continue to be one of the arteries of our region in the future," says Head of Transport Klaus Oesterling.
"If we want to bring climate protection and modern, efficient metropolitan mobility together - we have so far, but will have to do so more than ever - there is no way around public transport. And that means the sustainable, electric public transport that municipal transport companies in Frankfurt have been offering since 1884. Expansion of the network, maintenance of existing infrastructure, continued renewal and expansion of the vehicle fleet are the core business of the VGF and indispensable, future-proof tasks for the city," adds Michael Rüffer, technical managing director of the VGF.
The Frankfurt tunnel boring machine is driving two tunnel tubes, each approximately 850 meters long, starting with the south tube. In the process, "Eva" passes through the Güterplatz underground station and bores its way between Hohenstaufenstrasse and Mainzer Landstrasse to three meters in front of the sealing structure on the existing building under the Platz der Republik. The machine is then dismantled in sections and pulled back to its starting point through the previously constructed tunnel. After reconstruction, the machine will be sent on its way again to drill the second approximately parallel tunnel tube as well. There really is a lot of work ahead for everyone involved.
"The expansion of the U5 - and thus the development of the Europaviertel with an underground railway - is one of the most important infrastructure projects in Frankfurt for years to come. For VGF, it is a personnel and technical challenge that we are facing and where we can prove the efficiency of the municipal transport company. Because when it comes to implementing a modern and viable transport policy, VGF is an efficient and reliable partner for the city," says VGF Managing Director and Labour Director Thomas Wissgott.
How does "Eva" work? The giant tunnel boring machine resembles a factory working underground. At the front of the head is the cutting wheel. On "Eva" it has a diameter of 7.10 metres. This cutting wheel rotates in front of a steel cylinder, also known as a shield, which is approximately 9.20 meters long and works its way through the earth with the help of around 100 peeling blades and cutting rollers. The working face, the soil in the area of the cutting wheel, is supported by the material already removed - the earth slurry. This counteracts the forces from outside and prevents the uncontrolled collapse of the soil. The excavated soil is conveyed out of the machine by auger and conveyor belt. Directly behind the shield, concrete segments, so-called tubbings, are installed in a ring shape. They form the tunnel walls. At the last segment ring in each case, the machine presses off with the aid of hydraulic presses. This is how the tunnel is gradually formed.
The implementation of the ambitious project is in the hands of a joint venture (ARGE): the ARGE U5 Europaviertel, consisting of PORR Deutschland GmbH and the company Stump Spezialtiefbau GmbH. It is responsible for the shell construction of the underground station and the construction of the underground section. "We applied for this contract because we were able to contribute all facets of our competence and expertise, which we have acquired through many years of experience not only nationally but also internationally. As with any other inner-city metro project, we are facing the specific challenges. The road has not been easy so far, but what sets us apart is the competence, perseverance and creativity of our employees, which made it possible to reach this milestone," says Hans Wenkenbach, COO of Porr AG.
The tunnel work runs around the clock seven days a week. The duration of tunnelling is around one year.