WELL-known among urban planners around the world as one of Europe's first post-war new towns, the garden city of Tapiola 10km west of Helsinki, is entering a new phase of development. A €1bn regeneration project, which has attracted private as well as public funding, is transforming the centre of Tapiola into a commercial hub with a residential development, which will house more than 2000 people and a new shopping centre.

An equally transformative project is taking place below ground. Finland's largest infrastructure project, West Metro, will extend Helsinki's 21km east-west metro line 20km into Espoo, the country's second-largest city, accelerating regeneration and drawing investment and employment into its southern districts.

The cities of Helsinki and Espoo agreed to meet the costs of construction within their own boundaries, which gives Espoo an 85% share and Helsinki 15%. However, the Finnish government has agreed to contribute up to €200m towards the €1bn cost of phase 1 and €240m towards phase 2, which has an estimated pricetag of €801m. The project is being managed by Länsimetro, a public company owned jointly by the cities of Espoo and Helsinki.

WestmetroConstruction of the initial 14km phase from the current Helsinki metro terminus at Ruoholahti to Matinkylä in Espoo is on schedule for completion this month and testing is expected to begin in February, with public operation starting in August 2016. Phase 1 has eight stations, only two of which are located within the city of Helsinki, and is forecast to increase metro ridership by around 100,000 passengers per day.

Each station will have its own unique and distinctive architectural identity, making it easy for passengers to recognise their stop, but access routes, platform layout and signage are uniform at all stations to aid navigation.

Lauttasaari is located beneath Lauttasaarentie shopping centre in the middle of Lauttasaari island 5km west of the centre of Helsinki with platforms 30m below the surface. Koivusaari is the only sub-sea station on West Metro and at 30m below sea level is also the deepest. The station has been constructed under Vaskilahti bay south of the Länsiväylä highway and will serve the western side of Lauttasaari as well as the neighbouring island of Koivusaari. The line then continues into Espoo, serving the commercial area of Keilaniemi before reaching Aalto University station, which is situated beneath the centre of the technical university campus.

Tapiola station will become an important interchange with the bus network and construction of the metro is being carried out in parallel with major new residential, commercial and retail developments, which will transform this area over the next five years. New developments are also emerging around Niittykumpu station, while the terminus of phase 1 at Matinkylä will become a major public transport interchange for southern Espoo, with the area above the station undergoing redevelopment with a new bus station, shopping centre, housing and offices.

The bus network will be revised to feed into the metro and there will be no daytime buses between Espoo and Kamppi bus terminal in central Helsinki, which is currently one of the city's busiest bus corridors.

Preliminary construction began at the end of last year on the 7km five-station second phase from Matinkylä to Kivenlahti and the first station and the first tunnel excavation contract was awarded in September, when Länsimetro signed a €26.9m deal with Skanska Infra covering 1.5km of twin-bore tunnels, one escape shaft, and the station box at Soukka.

Like phase 1, residential developments are planned or underway around several of the stations on phase 2, which is expected to bring an extra 70,000 passengers per day onto the metro when it opens in 2020. The new line will provide a journey time of 19 minutes from Helsinki Central Station to Matinkylä and 29 minutes to Kivenlahti.

Tunnelling challenge

West Metro will run underground for its entire length and the two running tunnels each have an internal diameter of 5.6m to accommodate 1.2m-wide trackside emergency access walkways, a requirement for now-deferred driverless operation. Cross-passages are located at 150-200m intervals and the deepest escape shaft is 55m below the surface.

As the geology is primarily granite, tunnel construction is largely drill-and-blast with shotcrete lining. Most of the line runs at depths of between 20 and 30m, but reaches almost 60m on the sub-sea section between Ruoholahti and Lauttasaari stations. Phase 1 required the excavation of 4 million cubic metres of rock, the equivalent of 400,000 lorryloads of material, which is being used for land reclamation in Helsinki.

A number of challenges were encountered in tunnelling which pushed the cost up by €50m and delayed the project by six months. Geological conditions were poorer than anticipated in several areas and the surface of the rock was lower than expected, which meant additional concrete reinforcement was required.

As with the existing line, conventional ballasted track and 750V dc third rail electrification will be used throughout both phases of the extension. Tracklaying proved to be a logistical challenge because the lack of access from the surface meant the 120m-long rails could only be delivered using the existing metro line. Furthermore, the only suitable loading site was in the east of the city and rail trains could only operate during maintenance periods between midnight and 05.30.

All stations are designed for the installation of 1.7m-high platform screen doors, but these will not be installed in the short-term on phase 1 due to the cancellation of the automation contract with Siemens.

To provide additional fleet capacity for the expansion of the network, Helsinki City Transport (HKL) awarded CAF a €140.4m contract in 2012 for 20 four-car M300 trains, the first of which was delivered in March. Each 90m-long four-car set accommodates 576 passengers.

At present the Helsinki metro only has one depot, which is located at Roihupelto near Itäkeskus station, where the two eastern branches diverge. A second 600m-long underground depot will therefore be constructed at Sammalvuori north of Espoonlahti station to provide maintenance, cleaning and stabling facilities at the western extremity of the line.


In order to achieve competition between bidders, design and construction procurement was divided into numerous small contracts. For phase 1 Länsimetro let 17 contracts for tunnelling, 12 for construction, nine for electrical works, nine for ventilation and more than 20 for design works. Single contracts were let for track (awarded to Destia Rail, Finland) and third-rail (SPL Powerlines).

"Typically construction contracts were worth €20-30m each, which was a good size for Finnish bidders and a good size for us to manage," explains Mr Tero Palmu, Länsimetro's project manager for tunnels and track. "We felt we got stronger bids this way, and dividing contracts up resulted in more competition and better value. It's also about risk management - we wanted to keep everything in our hands and we can control lots of small contracts more easily than one or two big contracts."

Another advantage of this structure is that it embeds many of the functions that might normally be carried out by the managing authority within the contractors - Länsimetro only has 10 staff, five of whom are project managers. By contrast, project management consultant Sweco employs up to 60 staff and supervises all planning and tendering as well as supervising construction works.

However, lots of contractors inevitably means dealing with multiple interfaces. "Managing interfaces is the biggest challenge in our project," Palmu says. "It's true we have had problems and it can be challenging to control the flow of information and define the responsibilities of each party. It's a complicated network but we've been doing this for six years and we've learnt a few things. It's working well now."

West Metro will almost double Helsinki metro ridership and will plug Espoo into the capital's rail network, which looks set for significant expansion if Helsinki City Council's long-term urban plan comes to fruition. It also provides the sustainable transport links that will be vital to support the growth of population and employment in Finland's second-largest city.


Automation down but not out

IN 2008 and 2009 HKL signed contracts with Siemens for the automation of the existing 21km east-west metro line from Mellunmäki and Vuosaari to Ruoholahti and the extension to Espoo.

Unattended Train Operation (UTO) was initially scheduled to start on the existing line in 2013 and on West Metro in 2014. However, the project soon ran into difficulties because of the need to retrofit a mixed fleet of older M100 and M200 trains, which will operate alongside the new M300 sets currently being delivered by CAF. The M300s are equipped with removable cabs to enable straightforward conversion to driverless operation, but door spacing differs between the old and new trains, which created further challenges around the installation of platform screen doors.

HKL says these problems led to a major disagreement with Siemens over the cost of completing the work. In 2012 the project specification was revised, with full UTO dropped in favour of a driver controlling passenger doors and other functions.

However, escalating costs and the increasing risk of delay to the opening of West Metro led to the abandonment of the project earlier this year. In January Siemens made a further proposal to HKL, which involved a phased introduction of driverless operation, but this was rejected and the HKL board decided to terminate the contract in June. HKL and Länsimetro subsequently awarded Mipro, Finland, a €19.7m contract to supply automatic train supervision and electronic interlockings, together with passenger information systems, for both phases of West Metro with an option to supply equipment for the existing line.

HKL is now seeking damages from Siemens in a legal battle which is likely to rumble on for several years.

"The board of HKL decided it won't automate the metro in the near future but everyone agrees it is the only solution in the long-term because we need the capacity," says HKL CEO Mr Ville Lehmuskoski. "We can achieve 2.5-minute headways in normal operation but it is clear that in the 2020s we will need to automate the metro."

Current traffic forecasts indicate that maximum peak capacity will be exceeded on the western section of the existing line by 2022 and on the eastern section by 2024.

According to a study completed earlier this year, the line could be relieved by stepping up parallel bus services, and building the Laajasalo tram line could bring some degree of relief, but these are not viewed as alternatives to automation.

Pushing back automation will overcome the issue of retrofitting older trains, which are due to be replaced by new rolling stock in the next decade. However, HKL expects to operate the second phase of West Metro with UTO from the outset.