Did you know that there are currently 17 Spree tunnels in Berlin? There are already construction plans for tunnel number 18. Rotterdam has the Maastunnel and Berlin has the pedestrian tunnel Friedrichshagen – a tunnel under the Müggelspree.
The 17 tunnels under the Spree River were built despite the difficult subsoil in Berlin’s glacial valley. Two of the tunnels are not used today and two other tunnels serve only the various utility lines. One tunnel is for the non-public traffic of the government buildings and one tunnel is a non-public subway operating lines. What remains are 10 tunnels that can be used by the public: six for the subway, one for the commuter rail, one for the railroad, one for car traffic and one for pedestrians. And it was this tunnel that I had to see.
Where is the Spree Tunnel located?
The Spree Tunnel connects Kämmerheide near Köpenick with the district of Friedrichshagen. It runs under the Spree, which flows through Müggelsee here.
The tunnel entrance is not really conspicuous, which is perhaps also due to the fact that my gaze first falls on the water. The terrace on the shore invites you to make yourself comfortable on a bench and let your gaze wander over the water. Only at second glance does the rather inconspicuous entrance to the Friedrichshagen pedestrian tunnel catch my eye.
Spree Tunnel Friedrichshagen – the development
In the countryside just outside Berlin, the village of Friedrichshagen was a popular excursion destination around 1900. At that time, the Prahmfähre, a steam-powered chain ferry, connected Pfeiffergasse with an excursion pub to the other side of the Spree and the Spindler Tower located there.
On weekends, it could get really crowded. The ferry could transport 265 people, but when 40,000 excursionists were on site at peak times, there were considerable waiting times. So it was clear that a solution would have to be found soon. There were calls for a bridge or tunnel. A larger ferry or even another ferry connection was quickly ruled out; shipping traffic was already affected by the commuting ferry as it was.
Due to the existing shipping, the relevant authority rejected a bridge with a clearance of 14 meters. With the founding of Greater Berlin, the responsibilities changed and in 1925 it was decided to build a tunnel.
The tunnel construction
The tunnel under the Mügelspree was built from 1926-27 according to a design by the Berlin Bridge Construction Office.
A process was used that had never before been used in Germany. The first reinforced concrete tunnel was built in a caisson construction using compressed air. Since shipping traffic had to continue, it was decided to construct the tunnel tube in two parts on land. There were two reinforced concrete caissons, each of which was lowered to the desired depth within 34 days using compressed air. Only at their final position under water were the halves joined together.
The tunnel tubes are overfilled by about 1.5 meters. The difference in height between the tunnel floor and the water level is 8.4 meters. The upper edge of the structure is about 4 meters below the water level. The tunnel is 120 meters long and can be used only by stair access. There are ramps so that bicycles can be pushed.
History around the pedestrian tunnel
In April 1945, some Nazis tried to blow up the Spree Tunnel. A communist discovered the fuse and managed to cut it.
The southern tunnel exit was damaged by a bomb at the end of World War II, but the tunnel remained accessible.
Walk under the Müggelspree
After enjoying the beautiful view of the Müggelsee for a while, we were drawn to the entrance of the tunnel.
The entrance looks run down, although the last renovation was not so long ago. The lettering “Built and sunk 1926” is smeared and hardly recognizable.
A steep staircase leads into the tunnel. At the edge there is a gutter and a narrow concrete strip that is just enough to push a bicycle on. Strollers have to be carried, wheelchairs can only be carried down the tunnel stairs. The installation of an elevator is probably not possible for structural reasons and another solution (how about a stair lift??) has not yet been found.
For us it goes down into the tiled tunnel. It’s only a few steps through the tunnel tube until we’re back on the other side and have crossed a historic structure. I don’t think many users think when they walk through down here what an engineering feat tunneling was in its day.
We use the time on the other side of the Müggelspree for a short walk, just as the visitors did more than 100 years ago after their trip with the ferry.