Construction has halted on the Hawthorne Avenue bridge over Independence Boulevard that's part of the city's Gold Line streetcar extension project. Charlotte Area Transit system says steel girders were made the wrong size.

"Because the girders do not fit the specifications for alignment, bridge work has stopped. The vertical alignment of the girders is not in tolerance. This means, the curvature in the girders does not fit required contract specifications," CATS said in a statement.

The problem was discovered when workers found that the replacement girders did not align properly. CATS says the contractor, Johnson Bros. Corp. of Texas, is working with the manufacturer to fix the problem. A spokeswoman says the contractor is responsible for the cost of the error.

The Hawthorne bridge closed in July 2017 and had been scheduled to reopen this March. But now, CATS says it's uncertain when the bridge might reopen.

It's also not clear how the delay might affect the planned August 2020 opening for the $150 million Gold Line extension. CATS says it's trying "to restructure the remaining work on the CityLYNX Gold Line Phase 2 project to minimize overall schedule impact."

The Lynx Gold Line currently runs from the Transportation Center uptown, along Trade Street and Elizabeth Avenue, to Hawthorne Avenue and Fifth Street. The Phase 2 expansion will extend the line east across Independence to Sunnyside Avenue, and west to Johnson C. Smith University.

Future plans call for extending the Gold Line west along Beatties Ford Road to I-85 and east along Central Avenue to the former Eastland Mall area.

CATS says the bridge construction is safe — despite the girder problem — and it's safe to drive under the project.