Metro Considers Tysons Options
Tunneling Might Be More Affordable

By Lisa Rein
Washington Post Staff Writer
Thursday, January 19, 2006

The engineer overseeing construction of a subway line in Barcelona is visiting Fairfax County this week to offer advice on whether a planned Metrorail extension through Tysons Corner should be changed dramatically from an aboveground line to a tunnel.

The tunnel idea has been kicked around for several years as Metro, state and local officials mapped the path of a Metrorail extension from Falls Church to Dulles International Airport and beyond. But the idea was rejected as too costly. Under the current plan, less than a half-mile of the four-mile route through Tysons would be underground, with the rest at street level or elevated above the tangle of highways in the area.

Then last fall, Metro officials reconsidered tunneling as they learned more about a technique becoming popular with European transit systems. It's an engineering marvel that can bore through twice as much earth as traditional machines, drilling a hole almost 40 feet wide, instead of the 20 feet achieved during construction of subway tunnels such as Metro's. By excavating the two tunnels needed for the rail line at once, the new system could be more efficient, transit officials said.

It's not known whether the system would save enough time and money to lessen the cost of the project's first phase, estimated to cost $1.8 billion. There are also questions about whether a tunnel would affect a few neighborhoods in McLean.

"It's never too late to analyze a good idea if it's a good idea," said Roger Picard, project executive director for Dulles Transit Partners, a consortium of companies that would design and build the 23-mile rail line. Construction on the first phase, between Falls Church and Wiehle Avenue in Reston, is scheduled to begin in December.

Picard, who managed the $8.2 billion high-speed rail line between London and the English Channel tunnel, said he was skeptical that tunneling would be cheaper even with the more efficient machine because deep excavation is expensive. That's mostly because engineers cannot know all the conditions underground, such as the amount of rock, until they dig. Unforeseen difficulties can increase labor costs and cause delays. Also, tunnels require expensive ventilation that aboveground tracks do not.

Yet sending trains underground would have many advantages, among them less disruption to life in Tysons Corner during years of aboveground construction, less need to purchase land for tracks and stations and no utility lines to move. And an underground train line would avoid the visual impact of elevated lines, which some fear would be an eyesore in Tysons.

"There are some real advantages," said Fairfax County Board of Supervisors Chairman Gerald E. Connolly (D). "Construction can be 24/7. It's weather impervious. Aesthetically it has some advantages."

Metro first approached project officials about tunneling last summer as Virginia was looking for ways to cut the cost of the rail line. Virginia Transportation Secretary Pierce R. Homer asked state project officials to review the potential costs of the new approach.

In recent interviews, officials said they expect to have some estimates by February. The engineer with Dragados, the Spanish firm that has completed about half of a 22-mile subway addition in Barcelona, arrived in Northern Virginia last week and is continuing meetings with the project team this week.

The 4.3-mile tunnel would start at Magarity Road on the road that connects Interstate 66 with the Dulles Toll Road, just west of the West Falls Church station. It would plunge west under Routes 123 and 7, and end near Wolf Trap. That's roughly the same path of the planned line, except that the four-mile tunnel could also dip below some residential streets in the Hunting Ridge and Magarity Mews neighborhoods near McLean.

"They should bring the neighborhoods into the dialogue from the get-go," said Adrienne Whyte, a McLean area civic activist who monitors development in that area. "If this is in the consideration stage, why isn't it being discussed with the affected neighborhoods?"

Project officials said they have not determined how -- or whether -- those neighborhoods would be affected because they are focusing now on the cost, not the exact route. James Haggins, Metro's director of construction, said the neighborhood path was presented to project managers as one option that could reduce the length and expense of the tunnel.

Such a large boring machine would require excavating at 100 feet in some places, deeper than most points in the existing 106-mile Metro system. However it is built, the line would create two tracks large enough for two trains. Additional space would be used for station platforms or service or equipment areas, Haggins said.

One concern is that a shift in course could delay the start of construction. Preliminary engineering for the rail line is almost finished, and the project is awaiting federal funding this fall. But tunneling would call for a new design and possibly a new environmental review, both complicated and lengthy undertakings.

Connolly estimated that rising construction costs could add $50 million to the project each year it is delayed.

Paul Griffo, a spokesman for the Federal Transit Administration, said he could not assess whether "something that's not even in the pipeline with us right now" would face new regulatory hurdles.

Picard said his team considered a three-mile tunnel last year between the Capital Beltway and the Dulles Airport Access Road but concluded that construction would cost 50 percent more than the aboveground alignment. Haggins said he asked Dulles Transit Partners whether they had met with engineers who have used the new technology in Europe. "They said they had evaluated it only internally," Haggins said. "We were able to convince them to discuss it with Dragados," the firm working in Spain.

Most of those involved with the Dulles project agree that labor costs, soil conditions and materials are different in Northern Virginia and Spain.

Beyond a comparison of construction costs is another environmental factor that sets Tysons apart: The cost of street closures would be far higher if the line is built aboveground. Each time the state closes a road to traffic to allow crews to build the Springfield Interchange, it costs money to inform the public, direct drivers to alternative routes and hire workers to block roads.

Consider what would happen in Tysons, where redirecting traffic is anathema to retailers. "Our challenge here is that the Tysons businesses don't want us to tell their customers to go to Potomac Mills instead," said Sam Carnaggio, the state's project director for the Dulles rail project. "And people have to get to their jobs. That's a major, major difference."