This month's planned opening of the first phase of the Rail Park on elevated tracks north of Center City Philadelphia will be delayed by a few months so a pedestrian bridge over 13th Street near the park's entrance can be replaced.

The Center City District business association, which is leading the park's development, said in a release Tuesday that the replacement became necessary after rust and corrosion of structural beams were uncovered by crews renovating the bridge as part of the project.

The park's first quarter-mile section, running from near Broad and Noble Streets to a junction just past 12th and Callowhill Streets, is now scheduled to open sometime in the spring after the bridge is rebuilt.

CCD spokeswoman JoAnn Loviglio said that the cost of the replacing the bridge would not be known until a contractor is selected for the work but that it would be paid for by the city.

The rusted steel girders from the existing bridge will be repurposed to frame walkways and create planters for shrubs and trees along the park walkway, according to the statement.

A section of the bridge for auto traffic will be replaced at a later date after the park has opened, the CCD said.