SHARING SUCCESS

Ring Rail Line project,

A comprehensive Ring Rail Line, completed in 2015, serves as an important link between residential and business areas north of , spur suburban development in the area, while also serving .

BACKGROUND Finland. SUCCESS FACTORS Helsinki Airport has long needed a direct “Their construction is more of a challenge Juha Kansonen, Ring Rail Line rail link to Helsinki City center. In addition, than metro stations because the trains are Project Director, The Finnish the surrounding metropolitan area has been larger than metro wagons,” says Magnus Transport Agency, says that the Ring growing steadily, and the Finnish Transport Långstedt, the rail line’s Lead Designer from Rail Line has been a tough undertaking for Agency recognised that environmental, time- Pöyry. Safety in the tunnel will be best-in- all parties because such a track has never saving alternative to cars and buses should be class. Tunnels connecting the line’s two before been built in Finland. offered to people commuting to work. tracks will be built at 200 metre intervals, “Whilst we have previously executed many ensuring that evacuation to the adjacent tunneling and underground station pro- After assessing the options, a new Ring-Rail track can take place in exceptional jects for metro, the technical systems and Line was proposed. This will be an essential situations. safety requirements have developed component of the city’s rail network, that aims enormously over the years. Pöyry played a to not only function as an important route for Finland’s harsh climate and the location pivotal role in engineering the tunnel and commuters, but also spur the development of of the tunnel have added an extra layer of tunnel stations, in which we have suc- new residential and business areas in its challenges to the project, and there have also ceeded thanks to the commitment of the vicinity. The line’s foundation stone was been surprises along the way. expert engineers –even though there have laid in March 2009, and operating started in “When a train enters a tunnel in winter it been many challenges along the way”, 2015. brings along cold airflows that cause icing on Kansonen continues. the rock walls. In addition, the tunnel is not Pöyry participated in preparing both the only very close to the airport’s runways, but general and rail design and engineering also near the Päijänne tunnel that delivers plans, and is presently finalising the detail fresh water supplies to the city. As a result design for the tunnel and underground pressurised water will seek ruptures and stations. The job covers engineering for the weak points in the bedrock,” Långstedt track tunnels, the construction of two continues. stations and two station reservations as well as technical systems, which will not only The team encountered the biggest challenge improve traffic safety and flow, but also make in the project so far in the tunnel below the the journey a more pleasant airport’s eastern runway; microbe growth experience. which feeds on glycol. Glycol is used as an anti-freeze agent for aeroplanes. CHALLENGES “Biodegradation products of glycol shorten The rail line will run below Helsinki Airport the life of construction materials, which me- through an 8-km-long twin tunnel. The tun- ant that we had to come up with an innovative nel is not only unusually long, but it will also solution for the tunnel structures,” Långstedt house the first underground train stations in says.

KEY FACTS: Customer: Finnish Transport Agency and the City of Vantaa Cost estimate: EUR 738 million Completion: 2015 Type: Twin tunnel, drill and blast, four underground stations SOLUTIONS BENEFITS Track length: 18 km Pöyry has been able to find a wide range of Upon completion, the Ring Rail Line will Tunnel length: 8 km solutions. Due to the cold weather a 1-km connect an additional 200,000 residents strip of insulation has been placed on both and 200,000 jobs to the railway network. SERVICES: ends of the tunnel. The high pressure of the Daily train usage is expected to reach 50,000 • General planning and environmental Päijänne tunnel was combated with the pla- passengers by 2025. impact assessment cement of pressure-resistant grounding plate “The line offers an important route across • Bridge design in the tunnel. Construction was momentarily the city, improving public transportation in • Rail engineering halted due to the glycol that had permeated the area,” says Juha Kansonen. The rail line • Rock and geotechnical engineering the bedrock, and Pöyry proposed a concrete differs from a typical airport line in also being • Tunnel design tunnel within the tunnel. a local connection. • HVAC engineering “A precast concrete tunnel will be embedded “Airline passengers will make the journey • Electrical engineering within the bedrock, wrapped in an airtight together with everyday users, but at a much • Structural engineering film that is resistant to the harmful chemi- cheaper rate than a standard airport train,” • Telecommunications design cals”, Långstedt states. Kansonen adds.

Consulting. Engineering. Projects. Operations. Smart solutions across power generation, transmission & distribution, forest industry, chemicals & biorefining, mining & metals, transportation and water. 6000 experts. 45 countries. 150 offices.

Pöyry PL 4 (Jaakonkatu 3) FI-01621 Vantaa, Finland Puh +358 10 3311

www.poyry.com