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Silverline Phase III

Sub-consultant for NATM design.
Estimated cost: Commencement:
January 01, 2003
Completion date:
January 01, 2008
500 Arborway
Boston, MA 02130
United States
Technical data:
Geology description:

Made ground, peat, glacial till (cohesive, plastic), Boston Blue Clay and sand.

Geology types:
Bid cost: Final cost:
$550 million USD
Service areas:
Construction methods:
Tunneling under:

Silver Line Phase III is an underground extension of the Silver Line from the current terminal at South Station into Downtown Boston. The tunnels through Boston's Chinatown lie up to 25m below surface and include ca. 1400m long-running tunnels, two stations and complex underground junctions. The NATM design alternatives for LRT / Busway tunnels are located beneath existing subway stations and running tunnels. 3D modelling tools were utilised to create multiple alignments.

3D rendering of the Silverline Phase III alignment
NATM alternative beneath MTA's Chinatown Station