Copenhagen’s new circle line on the underground railway network puts technology and thematic design into its fabric.
Technology, architectural design, functional simplicity and sharp focus on safety. These are some of the defining features of the recently opened “Cityringen” circle line running 30 metres below the streets of Copenhagen.
Opened in September 2019, the new line comprises seventeen stations and dual tunnels of over 15 kilometers in length. The Cityringen line extends the former underground network of Copenhagen and connects the city centre with the districts of Vesterbro, Nørrebro, Østerbro and the city of Frederiksberg.
Copenhagen has had an underground system since 2002. The two lines, M1 and M2, run between Vanløse in the west, Vestamager, and Kastrup Airport in the south-east of the Danish capital. The opening of the Cityringen line connects the inner city districts with Frederiksberg and the central railway station.
Taking inspiration from the surrounding regions of the 17 stations on the line, each entrance was given a unique design.
With its objective of making the stations more than simply the constructed result of building specifications, but more in keeping with the environment as individually designed urban spaces, Arup designed the station entrances with an array of different colours and shapes. The aim was to provide passengers with clean lines of sight for a seamless street-to-platform journey and make the stations themselves pleasant civic spaces.
The architects used ceramic panels made by Moeding in the façade design of seven of the stations. Used for the first time in this application, the orange peel effect glazed surface emphasises the natural material and, thanks to its easy upkeep, is very well suited to construction projects of this type.
This effect was achieved during the baking process, which caused a wave-like relief to the glaze, creating a vivid surface that changes depending on the viewing angle and reflections. In addition to individual designs, the developer specified the use of a natural building material and the need for a minimalist façade requiring as little maintenance as possible. The lead-free clay and loam brick panels form part of a rapid rear-ventilated façade system that can be installed and removed simply without the need to follow a specified assembly sequence.
At the seven locations of Frederiksberg Allé, Gammel Strand, Copenhagen Central Station, Østerport, Nørrebro, Poul Henningsens Plads, and Vibenshus Runddel, the company used almost 12,000 of its ceramic panels coloured red, green, white and grey.
Stations with a theme
The common thread used throughout the design of the Cityringen was theming the station design to provide recognisable navigation aids to passengers. The underground authority, Metroselskabet, chose to use a shade of red that reflects the colour associated with the Danish State Railways (DSB) for all of the stations that provide a connection to the overland rail network, such as Copenhagen Central.
Other stations consistently reflect their surroundings at the surface level. The glazed panels coloured in different shades of green at Frederiksberg Allé station are a reference to the lime trees that line the avenue above the station.
Three stations, among them Nørrebro, were given white glazed brick panels, inspired by the numerous monuments at the nearby Assistens cemetery. Angular panels such as at Gammel Strand or colourful details on the bottom edges of the brick panels at Vibenshus Runddel station further highlight the design diversity that was used.
Kit Built Stations
Overseeing architects at Arup were a key element in the Copenhagen authority’s mission to become carbon neutral by 2025. The new line seeks to achieve this in part by encouraging more residents out of their car and onto a more environmentally-friendly mass transit network. Now that it has been completed, Cityringen ensures that the majority (around 85%) of Copenhagen’s residents will be within 600 metres of a train or metro station.
During the construction, Arup approached each station as being a gigantic kit of parts made up of a cost-effective construction system with individual, modular parts that can be easily assembled, installed or removed as required.
According to Arup, every element of the design had to work hard. Beyond their functional use as air vents, the asymmetric, sculptural skylights allow natural light to flood the stations and in a similar dual-use approach, the lighting design is fully integrated with the architecture and uses the angular ceilings as reflectors, complemented with bespoke LED lighting that helps avoid glare.
The architects were assisted by the proposed use on the line of the existing compact, driverless rolling stock as used on other parts of the Copenhagen underground system. The use of such trains enabled a more compact and efficient approach to be taken in the design of stations, tunnelling, services and equipment.
Another advantage of the modular “kit built” approach to station design is the ability to use the cladding as removable access panels to service ducts containing existing facilities as well as accommodating future communication systems as technology moves on in the future.
According to Anders Nøhr of Arup, the panelling system met the architectural requirements, saying that they chose the ceramic panels because, when used on a large scale, they reveal a highly distinctive material and surface structure with a relatively low weight and are an extremely resilient, robust, vandal-proof and age-resistant cladding system.
“Furthermore, the ceramic facade is a non-metallic cladding that allowed us to install antenna cables for radio communication in the 150-millimetre cavity behind the panels,” he says.
Now that the Cityringen circle line is up and running, it will be able to start fulfilling the promise to help the city of Copenhagen to take a further step forward in its goal of being climate-neutral by 2025.
Arup hopes to prove that the architecture of railway systems can contribute greatly to a city’s identity, with a design that can be maintained cost-effectively, long into the future.