Expansion of Zurich Stadelhofen railway system – The challenge of tunnelling in the centre of Zurich

Zurich Stadelhofen railway station is effectively a bottleneck in the city railway network that serves the Zurich area, a bottleneck the ‘Zurich Stadelhofen rail system expansion’ project aims to relieve by considerably increasing the capacity of the existing city railway system. Planning and implementation of new ambitious underground structures is therefore underway in the urban area next to and in existing structures while trains continue running. These include a platform access tunnel for a new track and a vaulted hall to act as link between the new and existing structures in the Zurich Stadelhofen railway station, a compressed air tunnel drive for a single‐track railway tunnel in groundwater‐bearing loose rock, a branch structure (also in loose rock) and two connecting structures that must be built around the two‐track railway tunnel which will remain in operation.