A journey of a thousand miles, it is said, begins with a single step. The same can be said of some government projects, such as the long-contemplated extension of the Washington & Old Dominion Railroad Regional Park from Purcellville to the Appalachian Trail.

The Northern Virginia Regional Park Authority has just taken that first step in hopes of opening the final, seven-mile segment of the W&OD trail in about three years. Currently, the popular hiking, biking and equestrian path runs 44 miles between Shirlington and Purcellville.

Park Authority Executive Director Darrell Winslow said money may not be the biggest hurdle in making the plan a reality. Rather, finding land for the skinny extension -- an eight-foot-wide paved path and room on either side for drainage -- could be the toughest challenge, he said.

Officials said they hope to have all plans approved by the Loudoun County government within two years, with construction time estimated at one additional year.

The park is now used by an estimated 2 million people each year. The new segment would link the Maine-to-Georgia Appalachian Trail to the W&OD trail and to other connecting paths extending to Mount Vernon and elsewhere.

The Park Authority began trying to complete the W&OD trail by asking the Loudoun government to amend its Rural Land Management Plan to indicate that the extension might be built from Purcellville to the Clarke County line, west of Bluemont.

That request received unanimous approval from the Planning Commission on Oct. 24 and has been forwarded to the county Board of Supervisors. In addition, the Park Authority must submit detailed plans and receive a commission permit -- similar to a permit issued to a public utility -- along with any other permits required by the Loudoun zoning administrator, county officials said.

Park Authority officials first must decide where they want the trail extension to go. The linear park follows the right of way of the defunct Washington & Old Dominion Railway between Shirlington, near Interstate 395, and Purcellville. But the portion of the train line's old path that is west of Purcellville is privately owned and probably unavailable for the trail extension, park officials said.

The agency said it may try to find a new path through the rolling hills or, more likely, it may try to persuade the Virginia Department of Transportation to let it use part of the right of way along Route 7, which connects Purcellville and Bluemont.

The Park Authority has budgeted about $168,000 to acquire land and has pegged roughly $300,000 to build the extension over several years. Winslow said the money comes in part from regular contributions by local governments based on their populations.

However, donations of land are a major source of aid to the agency and could make a big difference in the early realization of the Bluemont link, he said. "We've been very fortunate in the last few years" in receiving large farms and other donations, Winslow said.

He said that "unless something unusual happens" in local governments' budgets in the next few years, the money should be in place to build the park extension. "We don't have to depend on new funding," Winslow said.

The agency hopes to extend the paved trail from its current terminus in the center of Purcellville through the village of Bluemont and to the top of the Blue Ridge at Route 601. Winslow said a short unpaved footpath would extend from that point to the Appalachian Trail, which generally follows the Loudoun-Clarke county line in that area.

The W&OD train line, dubbed the "Virginia Creeper," ran between Alexandria and the Purcellville area from 1859 to 1968. Passenger service ended in the early 1950s. Local historian Eugene Scheel said the line was extended to the resort of Bluemont -- known as Snickersville before it was renamed by the railroad -- in 1900.

The Round Hill-to-Bluemont line was discontinued in 1939, but its heyday was relatively brief, ending in 1907 when the swank Blue Ridge Inn burned down, Scheel said.

Much of the current W&OD trail -- a segment from Vienna to Purcellville -- consists of one strip of pavement for hikers and bicyclists and a parallel strip for horses and riders. However, the final stretch to the Bluemont area would be a single, combined trail, officials said.

The extension to the Appalachian Trail "would be a tremendous boon," said Peter Harnik, vice president of the Rails-to-Trails Conservancy. Even though bicycles are not allowed on the Appalachian Trail, the W&OD extension would add to "a coordinated network of interconnected trails" and allow area residents to plan "all kinds of triangular and circular tours," Harnik said.

Two years ago, the Park Authority opened the eight-mile stretch of the W&OD trail between Leesburg and Purcellville at a cost of about $2 million. A $400,000 overpass at Route 28 in eastern Loudoun is tentatively slated for completion at the end of this year, 12 months behind schedule.