City Line

Building one of the most complex construction projects in Sweden to improve mobility in the heart of Stockholm

Location

Stockholm, Sweden

Client

Swedish Transport Administration

Project Status

Completed in 2017

Constructing Stockholm’s new City Line means excavating a 6 km rail tunnel between 10 and 40 m under the heart of the city, from Tomteboda in the north-west to Stockholm South Station.

This massive project is very intricate – for example, linking the City Station with the existing blue metro line involved blasting a connection tunnel through an area of bedrock that was only three meters deep, within a fixed four-month window.

Rail tunnel

6 km

depth

40 m

trains per hour

48

Overcoming Challenges

Our engineers were able to combine their extensive experience of infrastructure projects with market-leading expertise in the latest Building Information Modelling (BIM) tools. This project would not have been possible without the use of BIM.

Also, the new tunnel intersects the existing subway in two locations, so blasting requires the relocation of the subway track. The project’s geotechnical models are the most complex ever run in Sweden.

Using Visualization Throughout the Process

We are responsible for delivering the largest and most complex part of the project, providing a range of multidisciplinary services including tender documents, detailed design, project management and technical support during construction. Its three contracts cover about 2km of the line – the Norrmalm Tunnel, Norrström Tunnel and City Station.

Linking the City Station with the existing blue metro line involved blasting a connection tunnel through an area of bedrock that measured just 3m across, within a fixed four-month window.

We also demonstrated our market-leading expertise in the latest Building Information Modelling (BIM) tools. The number of tunnels, all going in different directions, could not be drawn in 2D, so 3D CAD was used to get the correct design. Then, all the geotechnical surveys, rock surveys and other information were added to the model, and it was used for collaboration between different disciplines.

The project’s geotechnical models are the most complex ever run in Sweden.