The Silver Line is facing additional delays in the opening of its first phase because of construction problems.
Metropolitan Washington Airports Authority announced that service that was originally scheduled to open last November, would not start until late spring or early summer.
The MWAA said deficiencies were found in seven of 12 categories with contractors.
As laid out by MWAA the list of areas that didn't meet standards includes: a failure to deliver certificates of occupancy for stations, power substations and the tunnel; performance issues with the Automatic Train Control System; failure to fully correct defects that impact operations; elevator and escalator problems and water leaks in buildings; as well as incomplete documentation for testing requirements and safety/security verifications.
Both phases have separate contractors and are separate plans, so the two operate independently.
Even though Phase One is behind schedule, construction on Phase Two has begun.
Preliminary assessments to determine the suitability of the ground as a foundation have started.
According to a release from MWAA "In February, crews installed six test shafts at three locations at the airport. Results will confirm the load carrying capacity of the foundation design for the aerial guideway, the support for the tracks, as it passes above ground through the airport."
Heavy construction on the Phase Two site is expected to begin later this year.
The first phase of the Silver Line includes four stops in Tysons Corner and one in Reston. The second phase, projected to be completed in 2018, brings the Silver Line to Dulles Airport and two stops in Loudoun County.