A tunnel formed within the flood barrier sea walls links the eastern limbs of Crossrail to complete a twin-track rail orbital of the Lower Thames Estuary from Central London. The estuary rail orbital with a 4sq.km floating solar array, cycle superhighway and promenade, including wayleaves for data storage, distribution and utilities, provides sustainable connectivity for over a million households, generating green-growth across the Lower Thames Estuary into Essex and Kent. Just 12km of new railway line creates a 132km Crossrail orbital of the Thames Estuary from Central London. The prow of this estuary orbital at Southend is as far East of Westminster as the terminal of Crossrail in Reading is to the West.
Construction undertaken in the tideway makes use of a rail head from concrete batching and casting facilities at an aggregates wharf nearby on the Isle of Grain. Spoil from the tunnel excavations is reused locally for embankments and flood bunds, enabling the embodied energy of construction and the environmental impacts to be kept to a minimum. The sea walls protect the estuary from tidal squeeze, preventing the loss of over 800 hectares of saltmarsh and intertidal habitat, thereby postponing the need for managed retreat on the Isle of Grain.