Rail Tunnels Beneath Highway 401

Expanding Rail Capacity in the Greater Toronto Area

The Highway 401 Rail Tunnel Project forms part of a major infrastructure programme to enhance rail transportation in the Greater Toronto Area. Delivered by STRABAG through its Canadian subsidiary, the project involved the construction of two railway tunnels beneath Highway 401, one of the busiest and widest motorways in North America, carrying 21 traffic lanes.

Awarded under a design-build-finance model, approximately 73 million (CAD 116 million) contracts commenced in 2017 and reached substantial completion in 2021. The project required the construction of two tunnels, each approximately 180 metres long, beneath the motorway with only 1.5 to 2 metres of ground cover and near an existing railway tunnel. Excavation was carried out using the Sequential Excavation Method (SEM), enabling safe construction under highly challenging conditions.

Once completed, the new rail infrastructure increased network capacity and improved operational efficiency, allowing passenger trains to travel at speeds of up to 145 kilometres per hour and freight trains at speeds of up to 56 kilometres per hour. 

Scope of Work

• Construction of two railway tunnels, each approximately 180 m long 
• Excavation using the Sequential Excavation Method (SEM) 
• Works adjacent to an existing railway tunnel 
• Delivery of the project under a design-build-finance model