After months of work and stress, it could all come down to price for the five groups seeking to build the second and final phase of Metro’s Silver Line.

On Friday, the Metropolitan Washington Airports Authority will have a meeting to review bids from some of the biggest names in construction competing for the contract to complete the rail extension, which eventually will reach Loudoun County.

The entire project is expected to cost $5.6 billion, and in screening this round of bids, MWAA is seeking the lowest figure for the second phase of construction. But the bids will be scrutinized to make sure they are accurate and realistic.

Ordinarily, such bid openings are low-key affairs at the authority, which is charged with overseeing the project. But the contract to build the second phase of the Silver Line is no ordinary sheet of paper.

“This is a tremendous milestone in the project,” said Patricia Nicoson, president of the Dulles Corridor Rail Association, who plans to attend the bid unsealing.

The first phase of the Silver Line will carry passengers through Tysons Corner to Reston.

Almost 20 years in the making, the 23.1-mile Silver Line will provide an important rail link to Dulles International Airport and into Loudoun. Leaders in Northern Virginia have long viewed the rail line as a project that will shape development and fuel economic growth in the region for decades to come. The first phase of the project, which runs from East Falls Church to Wiehle Avenue in Reston is set to be completed at the end of the year.

“We feel pretty comfortable that we’ve attracted the best talent in the world to bid for this,” said Tom Davis, chairman of the board’s Dulles Corridor Committee. “We just hope that the prices are within our estimates.”

In October, authority officials announced the five teams selected to bid on the second phase:

Bechtel Transit Partners, the contractor building the first phase; Capital Rail Constructors, made up of Clark Construction Group and Kiewit Infrastructure South; Dulles APC Railbuilders, made up of Archer Western Contractors, PCL Civil Constructor and Corman Construction; Dulles Metrorail Connectors, made up of Skanska USA Civil Southeast, Granite Construction Co., G.A. and F.C. Wagman, Trumbull and Facchina Construction; and Silver Line Constructors, made up of Fluor Enterprises, Tutor Perini, and Stacy and Witbeck.

The event on Friday will include a bit more fanfare than typical bid unsealings, and authority officials have reserved a large conference room. “It wouldn’t surprise me if there was a crowd,” said Christopher Paolino, an authority spokesman.

Even though the lowest bid will be known Friday, authority officials must study the proposal before officially announcing the winner.

There was no such hoopla surrounding the contract for the first phase of the rail project.

The also-rans won’t go away empty-handed. As long as their proposals meet required technical standards, they will receive$1.5 million each. Authority officials offered the incentive to increase competition and attract the best proposals.

The first phase of the rail project is expected to be completed at the end of the year, with passenger service beginning in January. The second phase is expected to be finished in 2018.