April 5 marks the fifth anniversary of the symbolic ground-breaking ceremony for the second main S-Bahn line. A lot has happened since then. But it was not until the end of January of this year that Deutsche Bahn (DB) began to dig deep at Marienhof.
One of three new underground stations for the second main line is being built at Marienhof. In the meantime, digging is under a 4800 square meter and 1.2 meter thick concrete cover in order to keep the noise and dirt in the surrounding area as low as possible. So far, the workers have dug almost five meters into the depths. This is where the barrier floor with the transition to the underground lines U3 and U6 is being built. After another two and a half meters, a concrete cover is poured again, under which the next level is then excavated.
There are five levels in total. It will be another two years before the excavation pit has reached its final depth of 40 metres. The tunnel boring machines then cut through the ground and meet at the Marienhof, where they are dismantled for transport.
500 to 600 cubic meters of excavated material are transported by truck via Maximilianstraße every day.
(Photo: Stephan Rumpf)
Around 50 truckloads of excavated material – which corresponds to 500 to 600 cubic meters – are currently being transported away via Maximilianstraße every day. The tires are cleaned in a car wash so that the trucks don’t spread the construction site dirt around the city. The fact that the excavation has only just started is due to the extensive preparatory work for the excavation pit. First, underground lines, so-called divisions, had to be laid, then archaeologists moved in to examine the area that was once built up and bombed during World War II. They recovered and documented 25,0000 individual items, including glasses, ceramics and remains of fabric.
After a noise protection wall up to four and a half meters high was erected around the construction site, construction of the outer shell of the station began. For this purpose, concrete walls were poured around the excavation pit, reaching a depth of up to 55 meters. In addition, 50 primary supports stabilize the structure in the ground during construction. At the same time, workers drilled 136 wells and groundwater measuring points to lower and control the water pressure. At a depth of 40 meters, the groundwater would exert a pressure of 3.5 bar on the construction pit. By pumping it out, freeing it from suspended matter and directing it into the western city moat, the pressure then drops to 0.7 bar.
Floors of the new train station are excavated level by level.
(Photo: Stephan Rumpf)
Work is similar at the main station, but here the DB transports the excavation by rail. Here, too, lines had to be laid before the actual work began, after which – despite some protests – the counter hall and the canopy, known as the “mushroom”, were torn down. Further preparatory work is currently being carried out on the transverse platform for the “integrated overall solution”, as DB calls it. In addition to the new underground S-Bahn station, a new entrance building, a new building for the Starnberg wing station and a shell for the planned U9 station are also being built at the main station.
Before other parts of the building are demolished, cable systems, lines and pipes, among other things, must also be dismantled or relocated at the main station. Instead, the shops are gradually moving out of the station. For the remainder of the construction period, DB will set up purchase and snack stands on the transverse platform to provide basic supplies for passengers. The DB Travel Center and DB Information will also be moving to the southern exit at Bayerstrasse later this year.
The DB has already come a long way at Laim station, where the first and second main routes will meet in the future. The first new platform is currently being built here, as well as a new track 1, which will be used by the S-Bahn on the first main route out of town in the future. Below the station, parallel to the Laimer underpass, the so-called environmental network tube for local public transport, pedestrians and cyclists is being built. Its shell already extends from the north side to the Laim station. In the further course of the section towards the city, two bridges are under construction in the track area.
In July 2021, the 95-meter-long steel tied arch bridge at the Hirschgarten S-Bahn station was the first completed structure on the second trunk line to be pushed into its final position. In the future, it will carry the tracks of the second main line over the southern ring.
For the construction of the eastern section of the second trunk line and the new tunnel station on Friedensstrasse, the detailed planning and coordination with the project partners and the Federal Railway Authority are still ongoing. When asked whether DB would really put the main route into operation in 2028, as announced, a railway spokeswoman said: “We’re checking that.”