Brunkebergstunneln – The Brunkeberg Ridge Tunnel

The Brunkeberg Ridge (Brunkebergsåsen) has been a major barrier between the Norrmalm and Östermalm neighborhoods since the beginning of Stockholm’s history.  

Brunkeberg Ridge

The southern end of the ridge was slowly hacked away over time because it was a good source of building material, and as the ridge disappeared, it became possible to follow a mostly level path from Norrmalm to Östermalm along the water’s edge.  The ridge never disappeared entirely, however, and it continues to be a barrier between the neighborhoods to this day.  As the city expanded northward, this barrier became more and more troublesome—to get from one side to the other, one either had to make a long detour to the water’s edge or one had to climb up and over the ridge, not an easy task when heavily burdened.

A not terribly accurate map from 1637 with Brunkeberg Ridge marked in red ***

 

I’ve found very little documentation about planning discussions about the tunnel.  Because it would have made transportation of goods and people between the two adjacent neighborhoods so much more convenient, the idea for the tunnel must have been born early in Stockholm’s history, but a lack of technology and funding would have made the tunnel a pipe dream until the mid 1800’s.

The first evidence I’ve found of the tunnel is in Wallström and Rudberg's General Plan for Stockholm from 1863.  This was Stockholm’s first attempt at a comprehensive city plan and while W&R’s plan generally ignores issues of terrain, it was very focused on traffic issues.  A tunnel through the Brunkeberg Ridge would definitely have facilitated transportation between the two districts.  

Wallström and Rudberg's General Plan for Stockholm 1863 included a tunnel *

 

I’ve found no evidence that Lindhagen’s plan takes Brunkeberg Ridge into account at all.  Lindhagen drew a major boulevard straight through the ridge, and it is unclear how this boulevard was supposed to negotiate the terrain.  Other parts of his plan involved removing sections of the ridge completely, so perhaps Lindhagen’s plan for the through-ridge boulevard also involved removing the ridge.  

Lindhagen's Plan from 1866 did not include a tunnel *

 

In all of the aftermath of Lindhagen’s proposal with all of the counter and counter-counter proposals and back-room negotiations, the tunnel appears in one lone scheme that part of the city council drew up in 1877.  Here, the tunnel is part of a conscious effort create efficient transportation between Norrmalm and Östermalm.  However, the idea was not popular with other city entities because a tunnel would need constant surveillance and lighting, both costly.  Also, it was understood that the tunnel would be hard to build due to the fact that the ridge is mostly made up of gravel.  

A city council proposal from 1877 where the tunnel reappears *

 

Eventually, Captain Knut Lindmark lobbied the city to build a toll tunnel through Brunkeberg Ridge.  Considering that the city had already considered building such a tunnel and voted it down due to excavation and operating costs, the city was probably more than happy to give Lindmark the right to build the tunnel and charge a toll.  He won the concession in 1884 and set immediately to work attacking the ridge from both sides simultaneously.  The tunnel proved to be much harder to excavate than Lindmark was prepared for—while the first parts of the tunnel were successfully (if slowly) dug through granite, the ridge soon proved to be mostly made up of gravel (as the city had already surmised), causing large sections to constantly cave in.  Lindmark didn’t give up, however, and he ingeniously solved the problem with an English freezing machine which had been invented to freeze lamb meat on voyages between Australia and England.  Because there was a lot of water in the gravel, large sections of gravel could be deeply frozen over night.  The next day, the frozen gravel could be removed in large chunks without the ridge collapsing into the tunnel.  The newly excavated section was then immediately shored up with scaffolding and a meter-thick concrete valve was poured to ensure that no gravel would collapse into the tunnel after the gravel thawed.  

Axel Ekbloms drawing of the tunnel construction from 1886 **

 

It took two years to build the tunnel and it opened with great fanfare in 1886.  The tunnel is 230 meters (755 ft) long, 3.9 meters high, and 4 meters (13 ft) wide—just big enough for heavily laden horse-drawn carts to pass.  At its deepest point, the tunnel is about 20m (65 ft) under the surface of the ridge.    

Oddly, the already built-and-in-operation tunnel was not included on the 1887 map of Norrmalm when the newly ratified city plan was drawn in.  

The 1887 map of Norrmalm with the newly ratified city plan drawn in is missing the tunnel *

Unfortunately for Lindmark and his stock company, the unexpected construction expenses meant that the toll through the tunnel had to be raised higher than was comfortable for most people.  People had been crossing the ridge for centuries, so they could just as well continue to climb the ridge to avoid  paying the hefty toll.  The tunnel company quickly went bankrupt and the city bought the tunnel, keeping it open and toll-free.  The city has renovated the tunnel every few decades since then.

the tunnel today

The Brunkeberg Tunnel was dimensioned for horse traffic and because it was not ventilated, it was inappropriate for car traffic.  The tunnel was quickly outdated for any other use than pedestrian and bike traffic, and when the Kungsgatan boulevard was built through the Brunkeberg Ridge just two blocks south of the tunnel in 1911, it rendered the narrow tunnel obsolete.   

One of the tunnel entries--definitely not dimensioned for cars!

 

However, the tunnel is still a useful pedestrian and bicycle connection today.  There is a steady stream of both pedestrians and cyclists in the tunnel these days, and there is often a busker or two playing music in the tunnel.  In most cities, a tunnel like this would quickly become a sketchy place to walk, but in Stockholm, it feels perfectly safe (I’ve never been in the tunnel alone late at night, it might not feel so benign then).  In recent years, the tunnel has even been the site of various art, sound, and light installations.  I love that the city keeps the tunnel open and that it is a half-secret yet very secure-feeling part of the pedestrian and bicycle network.

            

Sources: 

Gösta Selling, Esplanadsystemet och Albert Lindhagen: Stadsplanering i Stockholm åren 1857-1887 (1970)

Stahre, Fogelström, Ferenius and Lundqvist, Stockholms gatunamn (2005)

 

Images: 

 All images are my own except
* Gösta Selling, Esplanadsystemet och Albert Lindhagen: Stadsplanering i Stockholm åren 1857-1887 (1970)

** Stahre, Fogelström, Ferenius and Lundqvist, Stockholms gatunamn (2005)

*** Nils-Erik Landell, Stockholms kartor (2000)