Stockholm’s century-old railway bottleneck to be eliminated by 2017
Old Town and historic churches protected against damaging vibrations
The southbound railway line in and out of central Stockholm passes under the surface of the inner city on two tracks, established way back in 1871. Today, these two tracks serve an average of 24 long-distance, regional and commuter trains per hour – in each direction. This is a major bottleneck for Stockholm itself, but also for the entire national railway system.
The traffic system is extremely vulnerable to disturbances, to say the least, and regular maintenance is a challenge in itself. Since some 80 percent of Sweden’s train rides either start or stop in Stockholm, any such disturbance brings severe and costly national consequences.
Historic value protected against vibrations
In May 2007, after considerable political squabble, the government finally decided to build a second tunnel to be exclusively used by commuter trains, offloading the main artery – the Stockholm City Line. The new tunnel, scheduled for inauguration in 2017, is 6 kilometers (3.7 miles) long.
Two new stations are also being built, one of which will be located below the central railway station (Stockholm Centralstation), the main hub of Stockholm’s various traffic systems. Stockholm is widely known as the city on water, and the new line effectively incorporates a 400-meter-long sink tunnel under lake Mälaren.
Founded in the late 1100s, the city is rich in historic value. The new tunnel is located very close to the historic Old Town and the ancient Riddarholmen church. To safeguard this heritage, the construction phase was preceded by extensive risk analyses, resulting in strict limit-setting for vibrations and other risk parameters.
Some old buildings in the vicinity may not be in immediate danger for vibration damages, but due to their unique historic value, certain measures are being taken to be on the safe side. Ultimately, the responsibility for these assessments and any such measures lie with Trafikverket, the Swedish Transport Administration.
The new tunnel will take all commuter trains, allowing more regional and intercity trains to operate along the old line. Placing the commuter rail traffic into a tunnel of its own will also allow increased capacity for other national rail traffic through Stockholm Centralstation.
This video will give you a live insight into the tunnels under Stockholm city.