The City Line is one of Sweden’s largest railway investments ever. The project, which is expected to run until 2017, was commissioned by the government in May 2007. It is this long perspective that constitutes one of the main challenges. Traffic must be able to continue as normal throughout the entire conversion.
Vectura’s commission for the City Line concerns the complicated stretch of line from Älvsjö to Årstaberg Station. Described in simple terms, there are two bridges at Årsta and two tracks that have to change places in order for trains to be led on to the right one and from there into the City Line tunnel. The changeover for one of the tracks has to be carried out on a grade-separated basis in order to maintain a high capacity on the line.
There is a lot of traffic in the area. There is heavy congestion and the impact on the existing infrastructure – and the traffic – must be minimal. The most viable solution is a 1 km-long bridge that extends over the Älvsjö freight train shunting yard, Södra Länken and Årstaberg Station.
The present design stage focuses on how the traffic will be able to continue as normal during the course of the work. Protective gantries will be built to cover the tracks so that work on the planned bridge can be carried out without disrupting traffic.
Jan Wiå, Vectura’s project manager, has a wealth of experience:
“It is a large and complex project involving a wide variety of technical disciplines and with stringent demands to avoid disruptions in ongoing traffic. We are used to this kind of demand. I regard it as one of our major strengths. At most there will be some 50 personnel working on the project,” says Jan Wiå.
“Track design is one of the challenges. We have to consider existing tracks and structures, and there are strict demands on train speeds, gradients and traffic operation,” explains Jan Dahlberg, who is technical manager for the track component.
“We are creating a track solution that will also work for a planned extension of Årstaberg Station with two platforms some time in the future: one for northbound traffic and one for southbound services. This means that our solution is compatible for the future.”
A long and complex project
In order to guarantee quality in the project, Vectura has its own quality co-ordinator, Anders Berner, who is a survey engineer at our Stockholm office. It is his task to check that the project follows Vectura’s internal design process, which also conforms well with the sub-division of the City Line into design stages.
“Expressed in simple terms, it is my job to make sure that we actually do what we have said we will do. If I find any deviations, it is my primary task to report them to the Project Manager. If I find a shortfall in our internal routines, I report it to the person responsible for our operational system,” says Anders Berner.
The City Line is a long and complex project. Assignments that continue for as long as ten years are rare.
“Maintaining a high level of involvement and dealing with personnel turnover will in the long term be another challenge,” concludes Jan Wiå.