Vantaa tramway: Colas and Destia steer a €420 million light rail bet

Vantaa’s ice-slicked streets, in what feels like a quietly self-contained Nordic suburb, are being readied for a change that is about far more than getting from A to B.

Just beyond the perimeter of Helsinki Airport, Finland’s fourth-largest city is preparing to turn a major infrastructure gamble into a new urban pattern - with a French construction giant taking charge of one of the most complex and exposed parts of the plan.

A €420 million bet on a new tram corridor

Colas, the French construction group, has won the western section of Vantaa’s forthcoming light rail route via its Finnish subsidiary, Destia. The deal is worth €230 million for the opening phase and about €420 million across the project’s full duration, within a broader €750 million programme covering the entire tramway.

The Vantaa tramway will stretch roughly 19 kilometres, linking historic Tikkurila to Helsinki Airport while reshaping whole districts along the way.

The city is treating this as far more than a standard rail contract. For planners, the route is intended to function as the structural core of Vantaa’s growth strategy. It will tie Tikkurila - the administrative centre and historic heart of the city - directly to Finland’s main international hub, including a tunnel built beneath the current railway station. Rail services above will continue operating while teams excavate, form and cast concrete underneath.

The package of work is extensive: laying new track, reconfiguring and rebuilding roads, adding new cycle lanes, and comprehensively renewing buried infrastructure. Water supply pipes, sewers, electricity lines and telecommunications cables are all scheduled for replacement or enhancement. Beneath what will appear to be two straightforward rails, Vantaa will be refreshing the systems that keep 250,000 residents’ daily life functioning.

A city planning for 2050, not just next winter

On the northern edge of Helsinki, Vantaa has long been seen as an airport-adjacent satellite. Over the last ten years, however, it has matured into a substantial residential and logistics centre, home to more than 10,000 companies and over 100,000 jobs - with especially strong growth around the Aviapolis business district beside the runways.

The city expects a further 60,000 residents and 30,000 additional jobs by 2050, largely focused along the future tram corridor. Hitting that goal requires something more decisive than simply adding bus capacity.

The tramway is designed as a development spine: homes, offices and services will cluster around stops, cutting car dependency and shortening daily journeys.

Because the line will connect into the national rail network at Tikkurila and directly serve long-haul air travel at the airport, it links local districts into both national and international movement. For households, it promises easier access to schools, work and services without needing several cars. For employers, it strengthens Vantaa’s appeal compared with a peripheral city organised primarily around driving.

In Finland, planners commonly lean towards rail when they want to steer long-term land use. A tram line fixed in place is a durable signal to investors that the corridor is not going to move, whereas a bus route can be re-routed. That permanence often helps pull in housing schemes, office developments and mixed-use projects - which then supports more frequent services and higher-quality public realm.

Extreme worksites, Nordic edition

Building rails at −15 °C

Destia - once state-owned before it became part of Colas - already knows large-scale transport delivery in the Helsinki region. The company contributed to the Kalasatama–Pasila scheme, a significant urban rail and road corridor in the capital.

Even so, Vantaa’s tramway increases the challenge: construction in built-up neighbourhoods, a busy railway station that must remain open, and winters that routinely drop far below freezing.

At −15 °C, concrete does not behave as it does in milder weather. Pour too late in the day and curing can lead to cracking. Wind can strip heat from temporary enclosures in moments. Moisture can freeze on steel reinforcement. These constraints push Colas and Destia towards tightly controlled, carefully sequenced phases where timing is critical.

• Track slabs and structures require thermal protection while curing.
• Utility diversions have to be completed within narrow night-time windows so essential services stay operational.
• Heavy plant needs winter-grade hydraulics and fuels.
• Traffic management must align with snow-clearing operations.

To manage risk, engineers typically programme the most temperature-sensitive tasks into the shoulder seasons, leaving mid-winter for prefabrication, rail welding under protection, or insulated utility tie-ins.

A French group grounded in cold, heat and permafrost

Colas brings a wide international track record to this near-Arctic setting. Operating in around 50 countries, the group completes roughly 45,000 projects each year, spanning environments from Gulf deserts to Alpine tunnels. That breadth has driven the company to develop approaches suited to many climates and ground conditions.

In Saudi Arabia, Colas installed track on the Haramain freight line in desert conditions where temperatures rise beyond 50 °C. In Alaska, teams have delivered roads across permafrost, where errors in insulation or drainage can lead to long-term ground failure. In Quebec, crews carry out runway refurbishments within tight winter windows, sometimes moving materials via frozen roads or by aircraft when snow disrupts normal access.

Country	Project type	Challenging condition	Key technical response
Finland (Vantaa)	Urban tramway	Deep winter, live station, dense city	Phased works, winterised concrete and utility upgrades
Saudi Arabia	Freight railway	Extreme heat, sand intrusion	Stabilised ballast and temperature-resistant components
Alaska	Roads on permafrost	Frozen, unstable subgrade	Thermal insulation and careful drainage
Quebec, Canada	Runway upgrades	Polar winters, remote sites	Seasonal logistics and just-in-time supply
France (Alps)	Tunnel modernisation	Confined spaces, safety constraints	Ventilation, restricted working hours, staged closures

Decades of work on extreme sites give Colas a playbook for adapting materials, pacing and machinery to each climate, instead of forcing a one-size-fits-all method.

Why Finland is betting on trams, not only metros

Helsinki already operates a metro and has a long-established tram network. Vantaa, in contrast, has traditionally depended on buses, private cars and commuter rail. Committing to a dedicated tram corridor signals a strategic shift: prioritising reliable, rail-based capacity along a chosen growth line rather than adding more road space.

Trams fit this scale for several reasons:

• They can be delivered more quickly and at lower cost than underground metro extensions.
• Because tracks and stops are at street level, they influence street life rather than hiding it underground.
• They enable high frequencies without the skyline impact of elevated rail.

In Vantaa’s case, these advantages align with the objective of reducing car traffic on cross-town routes while still moving residents to Tikkurila and the airport and bringing workers into Aviapolis. Installing rails within the carriageway also supports wider street redesign - pavements, crossings and cycle infrastructure are often included within the same contract.

What this means for residents and travellers

Daily life along a transforming corridor

Delivery will take years, meaning communities will experience the disruption well before they see the benefits. Streets will be narrowed, bus routes adjusted, and noise screens set up and then repositioned as work progresses. For local businesses, customer numbers may fall during certain stages and increase later when stops open close by.

Authorities usually aim to reduce disruption through sequencing plans, temporary crossings and consistent public information. For today’s drivers, the works may initially feel like an added barrier. Over time, if the tram runs frequently and fares remain integrated with rail and bus, some journeys should move away from cars, easing pressure at major junctions.

Airport users will see a different kind of improvement. Rather than depending mainly on taxis, private shuttles or a single rail connection, travellers will gain another high-capacity route that serves neighbourhoods and employment areas - not just the city centre.

Climate goals and the hidden gains of digging up streets

Finland’s national climate objectives require cities to cut transport emissions. Shifting large numbers of car journeys to tram travel contributes to that, particularly given Finland’s electricity mix, which relies heavily on renewables and other low-carbon sources.

There is also a quieter advantage. When streets are opened up for a tram project, the city has a rare opportunity to upgrade underground services in a single, coordinated effort. Renewing ageing water mains can reduce leakage. Improved sewers can cope better with heavier rainfall linked to climate change. New ducts for fibre and electricity make later upgrades both cheaper and less disruptive.

This multi-layer approach - rail above, utilities below - often delivers value for decades, well beyond the short-term noise, diversions and congestion residents notice first.

What to watch next: timelines, risks and copycat projects

Attention now turns to programme certainty and cost discipline. Weather-driven stoppages, rising materials prices, or unforeseen conditions beneath Tikkurila station could all put pressure on budgets. If closures and detours last longer than stated, political and public scrutiny will intensify.

For mid-sized European cities growing around airports and logistics zones, Vantaa’s tramway will serve as a reference point. If it meaningfully shifts commuting away from cars, supports new housing delivery and keeps disruption within acceptable limits, leaders from the Baltics to Scotland are likely to take note.

From an engineering perspective, one point is clear: delivering complex rail works in severe climates depends less on dramatic machinery and more on sequencing and planning. Colas and Destia will need rigorous phasing, robust winter construction solutions and close coordination with rail operators to keep Tikkurila functioning while the station’s ground conditions are reshaped.

For those living along the route, the scheme is effectively a live rehearsal for how urban life might function by 2050: more everyday services within walking distance, fewer lanes dedicated to cars, and movement structured around rail rather than exhaust fumes. The winters ahead in Vantaa will show how well that ambition holds up against cold weather, traffic constraints and the day-to-day impatience of a city in transition.