Repair work is scheduled to start next week on the Silver Spring Transit Center, a project that is nearly three years behind schedule. (Sarah L. Voisin/THE WASHINGTON POST)

After a long winter of delay and dispute, repairs on the Silver Spring Transit Center are set to resume next week, Montgomery officials announced Thursday.

Fixes to the $120 million project, plagued by design and construction defects, has been delayed by cold temperatures and protracted disagreements among the county, Metro and contractors over how to proceed.

But after a series of meetings in recent weeks, Parsons Brinckerhoff, the project designer and engineer, has agreed to a plan for the strengthening interior beams and girders. In a letter to Council President Craig Rice, Montgomery chief administrative officer Tim Firestine said the county’s intent is to turn a finally-completed facility over to Metro by the end of the year.

Metro, however, has 60 days to do its own inspections and prepare the building for operations, which pushes any opening to the public into the first quarter of 2015, if not beyond.

The county’s announcement coincided with a call from one of Leggett’s Democratic primary challengers, Doug Duncan, for the firing of general services director David Dise, the lead county official on the project,which is nearly three years behind schedule.

In a letter to Leggett, released Thursday afternoon by Duncan’s campaign, Duncan said it was “time for someone to be held accountable, and make sure that this construction fiasco be given the highest level of attention to safely complete and open the transit center.”

Duncan cited recent council testimony by Dise that appropriate construction management had been employed on the project.

“His comments, however far removed from reality they may be, provide insight into why the people of this County have been waiting so long for this Center to open, since Mr. Dise thinks he has had the right approach on this project,” Duncan wrote.

Leggett quickly responded with a ringing defense of Dise and the assertion that Duncan was playing politics.

“If I thought Mr. Dise was responsible for the flaws and the resulting delays in the Silver Spring Transit Center, he would be gone already,” Leggett wrote. “David Dise is a skilled and dedicated public servant with a lifetime of experience managing projects, before this for Fairfax County and now for Montgomery. He recommended further inspections and pushed to address the challenges posed by the faulty contractors’ work and to move forward on the fixes needed....

“You can play politics on this if you want. I am not going to let politics get in the way of safety, getting this Transit Center open for commuters or protecting the interests of County taxpayers, period.