Clap much, much, much louder!

Turns out the biggest threat to the awesome, pants-optional Silver Line to Reston, Dulles and the hinterlands beyond isn't grassroot groups developers in Tysons Corner. Nope -- it's the Feds.

Federal officials remain skeptical of the plan to extend Metrorail to Dulles International Airport and might reject it, even though their consultants recently found that the proposal meets requirements for full funding, government and project sources said.

Those meddling, in-your-face, big-government types! Oh, wait.

Officials with the Federal Transit Administration say they are concerned about the price tag and the specter of another Big Dig, the Boston project built by the same contractor in charge of the Dulles rail line, which took years longer and cost millions more than planned, according to the sources, who spoke on the condition of anonymity because the negotiations are sensitive. In addition, the agency has been reluctant to promote large-scale transit projects.

Given the Big Dig's track record, we should probably thank our lucky stars that the Over, Not Under option prevailed. Fortunately, Silver Line supporters are on top of this problem. Right?

News that the rail plan is still at risk has surprised its backers, who said they thought the FTA was satisfied that the project's cost, ridership estimates, contract details and management met agency criteria. A consultant for the FTA, Hill International of Philadelphia, recently submitted two draft reports that sign off on a host of technical details, said sources who have spoken with the consultant.

Numerous sources close to the project -- in congressional offices, the airports authority and state government -- say their optimism soured in recent days as they began hearing from the FTA and Transportation Department officials.

FTA spokesman Wes Irvin declined to comment on the status of the project yesterday, except to note that a decision, expected at the end of the month, has not been made....

Some say the FTA has long been skeptical of expensive rail projects; in recent years, it has more often championed bus rapid transit projects.

Others point to a long-standing desire in the Transportation Department to move away from public investments in infrastructure. Peters, the transportation secretary, for example, refused to endorse a report published Tuesday by a bipartisan national commission on the future of the nation's transportation system. She instead issued a dissent decrying wasteful spending and the federal government's large share of the investment. She said she favored private investment and more tolling to control congestion.

Great. We've seen the effects of more tolling. And so far, the only private investment involving the Silver Line has been the $3 million ponied up to try and stop it -- and even that proved a pretty crappy investment, given that support for a lawsuit collapsed faster than property values in an exurban subdivision.

Just keep clapping, kids! We'll see you in bumper-to-bumper traffic.