One year after an engineer’s report called the Silver Spring Transit Center unsafe and unusable without major repairs, Montgomery residents have yet to hear from County Executive Isiah Leggett on how much the fixes will cost and when the problem-plagued bus and train hub will open, Democratic primary challenger Doug Duncan said Thursday.

“It’s time for answers,” said Duncan, standing before cameras in front of the fenced off entrance to the center on Colesville Road. “Silver Spring residents and community leaders have fought too long and hard for a vibrant downtown to have to wait for this mess to be cleaned up.”

The three-level center is more than two years and tens of millions of dollars behind schedule because of faulty design, cracked concrete, and steel supports missing from key segments of roadway. Contractors must also strengthen interior beams and girders to withstand heavy bus traffic, according to county officials.

Duncan’s appearance is his latest attempt to make the transit center exhibit A in his case against Leggett, calling it the most conspicuous evidence of his weak leadership and lax oversight.

Leggett, who had meetings in Annapolis Thursday, could not be reached for comment. His spokesman, Patrick Lacefield, said in a statement :“This is nothing more than the previous County Executive playing politics by seeking publicity for his campaign.”

Leggett has said on several occasions that he accepts responsibility for the troubled project. But he also maintains that he proceeded in responsible and deliberate fashion once problems with the center became apparent. That included hiring an independent engineering firm, KCE, in 2012 to evaluate the structure. KCE said the center could be made safe, but only with significant work.

After so many delays and setbacks, however, Leggett has avoided setting a date certain for the opening. Some work has continued through the winter months but a critical step--application of a special latex-modified concrete layer over roadway surfaces--cannot be completed until temperatures are consistently above 40 degrees. The application is expected to take four to six weeks.

But then the finished the facility must then pass muster with Washington Metropolitan Area Transit Authority (WMATA) which will be the operator. The transit agency has about 30 days to decide whether to accept the building once it is complete. WMATA has also been insistent that the county assume responsibility for added maintenance costs that may result from the design and construction issues.

That’s one reason Leggett and Dise have also avoided offering a final price tag for the center, which was estimated a year ago at $120 million. Leggett has pledged that taxpayers will not be on the hook for added costs.

Lacefield said that “all other things being equal, the facility could be completed, turned over to WMATA and opened by the summer.”

The transit hub is regarded as an essential element in the revitalization of Silver Spring that Duncan spearheaded during his three terms as county executive (1994-2006). Duncan’s administration received initial state funding for the project before it was handed off to Leggett in 2007.

“Like so many others,” Duncan said, “I’ve been disappointed by what I’ve seen.”

Duncan has worked as a consultant for Foulger-Pratt, the general contractor on the project. KCE held the firm responsible for the absence of reinforcing steel in two critical 10-foot-by-40-foot slabs in the center of the bus roadway. Foulger was also accountable for unacceptably thin concrete covering in some portions of the building, KCE said.

Duncan said that contractors and engineers “did not perform as expected,” but declined to criticize Foulger directly.