Four cranes loom beside the Dulles Toll Road, overlooking the Reston traffic and what will be the new Wiehle Avenue Metro station.

The cranes are at work on what developers say is the largest building project east of the Mississippi River -- at least six residential, parking and office towers overlooking the Wiehle station, which is expected to open in late 2013 with Metro's Silver Line.

The Wiehle Avenue plans are the most detailed offered so far by developers hoping to capitalize on new opportunities that will be created by the addition of seven new Metro stations extending west of Tysons Corner.

Contractors are digging out thousands of cubic yards of dirt, pouring 100,000 tons of concrete and working more than 1 million hours to develop the area around the station, according to Maggie Parker, a spokeswoman for developer Comstock Partners.

The 20-story buildings planned for Wiehle Avenue will include 450 luxury apartments, a 205-room hotel, two office buildings and a parking garage -- all within the next few years.

Nearly 20 percent of the apartments will be "work force housing" -- reserved for households making between $61,000 and $123,000 -- according to an agreement the developer struck with Fairfax County.

The seven-acre plaza will reshape the space between the shopper-friendly Reston Town Center and the new Metro station, which is what Reston residents wanted, Parker said.

"[Residents] were demanding world class architecture, something different from what you see driving up and down the regular roads," she said.

The Wiehle Avenue development plans were among a number of development options discussed last week by developers and local politicians who envision residential, hotel, retail and office space at every stop along the Silver Line, which will ultimate extend to Washington Dulles International Airport and Loudoun County.

Those new buildings will mean big economic gains for Fairfax County, local politicians said.

"The economics become a no-brainer to you as you look at [recent studies]," Fairfax County Supervisor Cathy Hudgins, D-Hunter Mill, said. "When you put in the correct use of housing and office and amenities, you get a return on that investment."