Repair work is finally underway at the Silver Spring Transit Center, but that hasn’t stopped the behind-the-scenes scuffling between Montgomery County and WMATA.

David Dise, the county’s general services director, confirmed that general contractor Foulger Pratt was on the Colesville Road site Wednesday, preparing fixes to two key roadway slabs that were found to have no pre-tensioned steel supports.

The plan, developed by a working group of county officials and contractors, is to pressure inject the slabs with fresh concrete and place some kind of overlay on the surface. Later this summer, workers will reinforce beams that are cracked or inadequately covered with concrete.

Construction and design issues have thrown the $120 million bus and train hub more than ten years behind schedule and tens of millions over budget.

Under the terms of their memorandum of understanding (MOU), WMATA gets 15 days to review and comment on changes in design proposed by the county. After that, the changes are deemed approved.

WMATA had agreed to expedite the review and get it done in five days. But Dise said the transit agency never responded, except to say that it wanted the strips completely removed and rebuilt.

“Unfortunately, the County is left with the impression that WMATA does not seek to engage in the conferral process contemplated by the MOU,” Frank Lunsford, Dise’s building design and construction contract administrator, wrote to WMATA deputy general manager Robert Troup on Tuesday.

Dise said WMATA has also asked for a specific stress test on selected girders and beams that the working group said did not have a sufficiently low margin of error.

WMATA is supposed to take over the center from the county and operate it as part of its regional system once it is deemed ready to open. But the agency has threatened to back out because of misgivings about long-term durability and maintenance costs.

Metro spokesman Dan Stessel said in a statement that it continued to work with the county “on a resolution of issues.”

“The County has requested clarification on our proposal, which we will provide,” Stessel said. “In addition, we are asking for more detail on their proposed fix. There are many variables to remediate and fix the identified deficiencies, so WMATA will evaluate all options ensuring the SSTC is acceptable for service.