Category: procurement

At Örbyleden in Hökarängen in southern Stockholm is the the entrance that is used to bring machines and workers down into the tunnel, and take out the blasted rock. The new tunnel will be 2.5 kilometers long and is planned to be completed by the end of 2024.

Click here to read more about the project

Groundwater is a major concern when building a tunnel. To seal off water leakage, a technique called grouting is used. When grouting, long holes are first drilled diagonally outwards in the rock in front of the tunnel front. For each grouting session, about twenty holes of 24 meters long are drilled. Then cement is injected into the boreholes. The cement finds its way into cracks and cavities in the rock and prevents groundwater from leaking into the tunnel. This process can take up to ten hours.

In the yellow machine, a so-called grouting platform, the cement used in grouting is mixed. The white bags contain dry cement that will soon be mixed.

When the grouting is complete, it is time to drill holes for blasting. A computerized drilling rig drills up to 250 holes into the rock, with precise length and position settings. It usually takes between five and seven hours to drill all the holes.

Before blasting, workers load all the holes with igniters and explosives by hand. They use a lifting crane to reach the higher holes.Each blast advances the tunnel by five to ten meters.

After blasting, all the blasted rock must be unloaded. After each blasting, workers unload 1200 to 1600 tons of rock. This is a quieter job that can be done at night.

Underground, it is hard to keep track of the blasting direction. That’s why the measurement technician plays a vital role. They measure the tunnel direction and ensure that it follows the right course and shape.

Sometimes some rocks are not fully blasted away. In that case, workers mark the protruding rocks with spray paint. Then they do a small extra blasting before resuming the work as planned.

Then the tunnel needs to be secured. First, workers remove loose stones by scrapping. Then they spray concrete on the roof and walls to prevent new stones from falling down. Finally, they drill long bolts into the rock wall to stabilize it. Then they repeat the whole process from grouting.

The Högdal depot is being expanded

When the metro system in Stockholm gets longer, more trains are needed. The Högdals depot needs to be expanded to accommodate the new trains. A new track tunnel is also being built to connect the depot and the metro to Farsta, so that trains can enter and exit via both Högdalen and Hökarängen. The entire work on the expanded depot in Högdalen will be completed in 2026.

The expansion of the metro system is well under way throughout the Stockholm area. Högdalen in south Stockholm is home to one of the most important construction sites for making the new metro system a reality – this is where the Högdalen Depot is being expanded to handle many of the new trains that will operate the new metro services.  

Here, you can watch a video that better explains what a depot is, why this one is being expanded and how it is being done (In swedish).

“Once the metro expansion is finished, more trains will need to be cleaned, serviced and stored overnight. The depots are an incredibly important part of the ecosystem, and without them, we’d have empty tracks and stations because the trains would stop running. The depots are quite simply the heart of the metro system, ensuring that traffic can flow around the metro network,” says Henrik Unosson, project manager for the new metro system.

Come 2030, you can be 100 metres below ground at Sofia station, on your way from the lift from Stigbergsparken towards the platform and the metro services heading south. On this particular day, perhaps you have plenty of time, so you take a good look around. Perhaps you think, “What a great combination, that turquoise wall and gold-coloured letters,” while also wondering who came up with the idea.  

“The artists have been involved in the process since back in 2015. They’ve worked closely with the architects and engineers to ensure that the artwork is an integral part of every station. The artwork in Stockholm’s metro system is important, and we’re proud to be continuing that tradition with the world’s longest art exhibition,” says Martin Hellgren, who is responsible for all the stations being built when extending the Blue Line south from Kungsträdgården.  

Realistic for travellers

However, the new images do not simply show the artwork. They have been produced from the computer model used as the blueprint for the entire new metro system. They show the scenes as seen from eye level, and the colours and textures have been processed and reviewed by the artists.  

“We use angles that are relevant and that provide future travellers with as realistic an image as possible. We also want to show things that we’re asked about, such as how the lifts at Gullmarsplan and Sofia will work,” says Martin. 

Now, you’re sitting on a train heading south, that same afternoon in 2030. At Gullmarsplan, you lift your eyes from your screen – you’re soon at your destination – and see just how beautiful the station looks. “I wonder what that’s supposed to represent,” you think, but there’s no time to find out, it’s your stop, Slakthusområdet. Perhaps you look down now, remembering an article you read a long time ago. “The floor really does look like ice that someone’s skated across. I wonder who came up with that idea?” 

Here, you can see all the new images and find out the names of both the artists and the artworks. 

Sofia

Artists: Peter Johansson and Barbro Westling
Name of the artwork: “Flux”

Sickla

Artist: Anna Lerinder 
Name of artwork: “Utblick och riktning” (“View and Direction”)  

Järla

Artist: Cilla Ramnek 
Name of artwork: “Direction Home”  

Nacka

Artist: Thomas Karlsson 
Name of artwork: “Elefanten och Noshörningen” (“The Elephant and the Rhinoceros”)

Gullmarsplan

Artist: Jesper Nyrén 
Name of artwork: “Windows”

Slakthusområdet

Artist: Helena Isoz 
Name of artwork: “Åkning” (“Trip”)  

In 2014, 16,000 Stockholmers voted on the colour of the new line between Odenplan and Arenastaden – and Yellow won. At the time, the plan was for a separate line with shuttle traffic, although this was changed in 2016. Instead, the line will continue south from Odenplan on the same tracks as the Green Line.

You can take a closer look at the future metro map here.

“Since then, we’ve discussed internally whether the Yellow Line should be part of the Green Line. Now, though, the Public Transport Administration, which is responsible for the actual metro services, has decided that this is a good time to make this change. On the one hand, we have a new line that needs a new colour, and on the other hand, the time is approaching to start running metro services to Arenastaden. So, it’s a good idea to decide this now,” says Niklas Bergman, head of FUT (Förvaltning för utbyggd tunnelbana), the administration responsible for the expansion of the metro system.

Accordingly, the future metro map is being changed. The Green Line will have a branch to Arenastaden, and the most recently decided line between Fridhemsplan and Älvsjö will be a Yellow Line.

“Since the metro to Älvsjö is a separate line, it’s good for it to have a colour of its own,” says Niklas.

“At the same time, it’s great that the colour that Stockholmers voted for almost ten years ago will remain on the metro map,” he ends.

The decision on the colour does not affect the routes or future services.