Why Going Underground Makes Sense in Tysons Corner

Virginia Gov. Timothy M. Kaine (D) has an opportunity that's rare for political leaders: He can change his mind and become a hero.

In September, he chose not to pursue the tunneling option for Metrorail's Orange Line extension through Tysons Corner because he feared losing federal transit funding and delaying the project, now envisioned as an elevated line.

Now he can justify revisiting his decision and doing the right thing, thanks to new information and circumstances that emerged in the past few weeks.

Knowledge in hand today reveals that the tunneling option compares favorably with the elevated rail-line option. A tunnel could be built more quickly and at a lower cost than an elevated line, would be less expensive to maintain, and would be environmentally and aesthetically superior.

Consider new factors that the governor can act on.

The Federal Transit Administration has said that Virginia still has time to analyze and choose between building an elevated or underground line through Tysons. In a letter to Reps. James P. Moran (D-Va.) and Thomas M. Davis III (R-Va.), FTA Administrator James S. Simpson wrote: "FTA is willing to hold the aerial design in Preliminary Engineering while the Commonwealth decides whether to proceed with the aerial or tunnel option."

The final design can proceed only after the FTA determines that the preliminary design is highly likely to comply with federal regulations regarding transportation and land-use effectiveness, financial feasibility, timing and environmental impact.

Mindful of these policies, TysonsTunnel.org, a non-partisan, not-for-profit advocacy organization representing citizens, businesses and property owners, is confident that the tunnel would allow the Commonwealth to comply with federal requirements. It makes this assertion after raising $3.5 million for a consortium of highly qualified consulting engineers, architects and tunnel construction experts to thoroughly but quickly design the Tysons segment of the Metro extension.

In January, after working for three months, the team completed its A-to-Z engineering study for a 43-foot-diameter, single-bore tunnel through Tysons, including environmental analyses and architecturally ingenious designs for the four Tysons Metro stations. Station sites and tunnel alignment are similar to those for the overhead rail.

The key is large-diameter tunnel boring machines, a technology developed in Europe and used extensively and successfully around the world. More than 100 feet long, these gigantic machines can rapidly chew perfectly round self-supporting holes through dirt and rock, conveying excavated material backward to dump trucks while lining the bored tunnel with either sprayed-on concrete or prefabricated concrete panels.

I have seen the full set of design documents -- a whopping 786 sheets of drawings, a dozen technical reports, cost estimates. They are comprehensive and compelling.

The tunnel team has leveled the playing field for the competing options. The 3.4-mile tunnel (the total length of the extension to Dulles Airport is about 23 miles) through Tysons Corner has been designed to the same level of engineering development as the design of the elevated line, thus enabling the Commonwealth to make a fair comparison.