Railway Track & Structures - November 2007 - (Page 24)

by Mischa Wanek-Libman, assistant editor one tunnel The Seattle area prepares for its mass transit future with the opening of the Downtown Seattle Transit Tunnel. Joint service, n September 24, two years to the day after it closed, the Downtown Seattle Transit Tunnel reopened for service, on time and on budget. Its reopening marks a rare occasion in the rail industry: A single tunnel used for bus and rail service. “It was good planning and incredible coordination by all of our contractors,” said Bruce Gray, spokesman for Sound Transit, of the tunnel retrofit project. The $85-million tunnel project is part of a larger 14.7-mile, $2.4-billion light rail project to run from downtown Seattle to Sea-Tac International Airport. The 1.3-mile tunnel, which originally opened in 1990, was retrofitted for joint bus and future light rail service. According to Gray, this is the first time anywhere in the country where one tunnel will serve dual transit roles at the same time. O The finished project with the new roadbed, lighting, communications and signage in the transit tunnel’s Pioneer Square Station. Work done “We had a lot of different things going on, it was more than just laying the track and getting the power systems installed,” said Gray. The 17-year-old tunnel’s electrical, mechanical and safety systems were upgraded, new signage was installed, along with an entirely new communications system, 18,000 feet of rail were laid and more than 20,000 cubic yards of concrete were poured. More security cameras and a new public announcement system were also installed. “We didn’t change the structural look of it, but it looks better because we upgraded all of the lighting systems. There was some water damage that had 24 Railway Track & Structures crept in over the past 17 years and we did a lot of work to get back behind the walls and clean that up and get everything back up,” said Gray. The station’s roadbeds were lowered 18 inches to accommodate level floor boarding, meeting an ADA requirement that allows level access from the platform on or off of trains and buses. The new rails that were embedded in concrete were fitted with a rubber boot to hold any stray electric current that can cause deterioration to the concrete over time. In addition to all the retrofit work that was done, a new 500-foot “stub tunnel” was built under Pine Street between Seventh and Boren Avenues. According to Gray, the new stub provides two essential components to future light rail service: It allows a place for trains to stop and reverse direction and it also provides a starting point for a 3.1-mile light rail extension going north. The extension will have two light rail tunnels to stations in Capitol Hill and the University of Washington. A cut-and-cover technique was used to build the stub tunnel. After the tunnel was dug from the surface, it was covered with decking to allow overhead traffic to pass while work continued below. Because trains and buses will be using the same platforms when light rail service starts in 2009, communication became a top priority of the project and an entirely new control system was installed as part of the upgrade. “From the operations base you can see exactly where every train and every bus is www.rtands.com November 2007 http://www.rtands.com

Table of Contents Feed for the Digital Edition of Railway Track & Structures - November 2007

Railway Track & Structures - November 2007 Contents On Track Industry Today Supplier News AREMA News NRC News TTCI R&D Seattle Retrofits Downtown Transit Tunnel Switch Stand, Switch Machines Planning M/W with Modern, High-Tech Tools Products & Literature People Calendar Advertisers Index Sales Representatives Website Directory Professional Directory Classified Advertising Chicago Perspective

Railway Track & Structures - November 2007

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