Virginia officials plan to announce next week whether they will pursue the construction of Metrorail above or below Tysons Corner, a milestone decision in the future of the Fairfax County community and the $4 billion rail extension.

After a lengthy period of complex wrangling on costs and feasibility, the debate on whether to dig a massive tunnel under Tysons or build the four-mile stretch on an elevated track could be nearing an end. The project is part of a larger venture to send rail to Dulles Airport and Loudoun County.