Test trains for Metro's Silver Line hit objects along the new track beds that weren't supposed to be there, though rail officials say the construction is going smoothly and the first phase of the line is still set to open at the end of the year.

A test train outfitted with fingerlike extensions along its surface twice traveled the length of the first Silver Line phase -- from East Falls Church to Reston and back -- and in both of those tests the train's extensions hit objects installed too close to the tracks.

In one instance, the train hit a handrail along a walkway in a Tysons Corner tunnel. In another, it hit a switchbox near a fence on the track bed, Dulles Rail project manager Pat Nowakowski said.

The train hit other objects as well, though Nowakowski said he couldn't remember what they were. But the train wasn't damaged or derailed, because only the extensions hit the objects.

"We need to make sure everything we build would accommodate that worst-case situation in terms of a rail car leaning to the left or the right," Nowakowski said. "They told me that all but one item from the trip in February was fixed the next day. These aren't big deals or catastrophic."

The top official at the Metropolitan Washington Airports Authority, which is in charge of constructing the Silver Line, said he's not worried the test results will hurt plans to open the Silver Line by year's end.

"Occasionally someone will hang a railing in the wrong place or put an electrical box in the wrong place," said airports CEO Jack Potter, who informed the airports authority of the test problems at a meeting Wednesday. "It's kind of common that things are slightly out of kilter that can be adjusted."

The test train will run along the Silver Line once more before crews try out a regular train on the tracks, Nowakowski said.

Silver Line test trains have been involved in two other recent incidents on the Orange Line, but both airport and Metro officials say they were Metro's responsibility. In one case, a test train cut cables near East Falls Church, causing emergency repair work and delays into the morning rush hour. In another, two Metro track workers were nearly hit by a test train that did not give proper warning that it was approaching.