Seattle LRT system starts with bus tunnels

CASE STUDY: An extensive light rail network in Seattle began in the late 1980s with excavation of the Seattle downtown bus tunnels. Several subsequent extensions for Sound Transit in Seattle included the deep Beacon Hill underground station on the extension south to Tukwila; TBM drives for the U-Link and North-Link extensions; and the EastLink services that share space with highway traffic through the Mount Baker Ridge tunnel and run under the streets of Bellevue in the Line’s new SEM tunnel.

Read more about the excavation of the Seattle bus tunnels and the start of metro systems for other cities in the USA in the 1980s, 1990s and early 2000s in the TunnelTalk Special Edition USA Focus magazine published this month. Coverage includes excavation of the running tunnels and metro station under the Minneapolis/St Paul Airport in 2002 and the Cityplace underground link on the Dallas, Texas, LRT system in 1992.

The Special Edition also reviews the planning, design and excavation of early CSO networks and under sea effluent outfalls in the 1980s, 1990s and early 2002s for Boston, Milwaukee, San Diego, and the Chattahoochee, Nancy Creek and West Area CSO projects for Atlanta, Georgia.

The Case Studies review the planning and funding of projects by the owners; the designs and types of contracts developed by the consulting engineers; and the equipment, materials and methods employed by the appointed contractors. The Special Edition is a walk through history to know how the projects of today in the USA are being shaped by the projects of the past.