Cologne Stadtbahn - Future Expansion

Future Expansion

The current expansion project under construction is a new North-South tunnel (Nord-Süd-Stadtbahn, NSS). On March 3, 2009 the building of the City's archive collapsed into a Stadtbahn's tunnel under construction on the Severinstraße, killing two people. Poor construction, the theft of necessary iron reinforcements and several ground water break-ins into the tunnel, which were not reported and not controlled properly by construction supervision, are among the alleged causes for this catastrophe. Because of the ensuing delay in construction, the opening of the NSS is estimated for 2015 or even as late as 2017. In order to make use of already completed tunnels and stations, a shorter service running from Dom/Central Station to Rathaus (city hall) is planned to start operation in December 2012, re-routing line 5 from its current terminus at Reichenspergerplatz to serve the new NSS. A further expansion to Heumarkt could be operated from 2013. The extra cost of approximately 4 million Euros is planned to mitigate the negative perception of the NSS project due to the collapse as well as budget increases, late completion (originally planned for 2011) and disruption. Other partial openings are not deemed feasible before the complete opening in 2015/2017.

The new 3 km long tunnel will be the first newly built line since the opening of the original downtown tunnel in 1968. Every line opened in between had been just a replacement for current or previous surface lines.

The oldest tunnel of the Cologne Stadtbahn is currently served by 30 trains per hour in each direction. Many consider this beyond the tunnel's capacity. Because the tunnel was built using a cut-and-cover technique, it follows major roads distant from the old city center with its narrow alleys. To solve both problems, an additional pair of tunnels was bored directly underneath the historic downtown areas. As a bonus, travel time of line 16 will decrease by about 10 minutes, because the NSS enables it to avoid the detour from Ubierring to Barbarossaplatz, only to return to the Rhine at the Central Station. It is also the final step in the separation of the high-floor and low-floor networks.

In order to avoid the possible destruction of archaeological artefacts underneath one of the oldest cities in Germany, the NSS was bored down to nearly 30 meters below ground level. At the location of the future stations however, archaeological digs were still required and are cited as one of the reasons for the already significant cost overruns. While initially estimated to cost around 600 million euro, the current price tag is calculated at around 960 million euros. Because the second stage, connecting the tunnel to the line along the Rhine river has not yet been tendered, but is expected to cost another 100 million, total cost is likely to exceed 1 billion euros.