PAWTUCKET –– An issue of liability has postponed the planned replacement of the Conant Street Bridge, closed for the past 19 years, Mayor James E. Doyle said Friday.

The bridge crosses railroad tracks, Doyle said, and Amtrak owns the right of way. He said Amtrak fears getting sued if there were an accident associated with the bridge demolition and construction.

He said Amtrak requested legislative protection, but the General Assembly is not in session, and it might take until next year for the legislature to act.

Michael P. Lewis, director of the state Department of Transportation, confirmed the liability hurdle, but said the delay would not be inordinate. He said that even if there were no problem right now, advertising for bids and awarding a contract would stave off the beginning of construction until next spring anyway.

The Conant Street Bridge was built in 1913 and carries Conant Street over Amtrak and the P&W Railroads between Mineral Spring Avenue and Barton and Weeden streets in Pawtucket. The existing bridge was closed to traffic in 1990. It carries gas and water lines with electric, telephone, and cable lines overhead.

The new bridge will be a single span truss structure with steel floor beams, steel stringers, and a concrete deck. The new roadway will have two 13-foot travel lanes and two 5-foot-wide sidewalks, the DOT said in a news release.

The new bridge will be made of weathering steel which will develop a protective patina of rust over the base steel and will therefore require less maintenance. New concrete abutments will also be built to support the new truss structure. The bridge will carry the same utilities as the existing bridge.

Additionally, as part of the project, most of Conant Street will be repaved and the sidewalks reconstructed from the east abutment to just short of the Mineral Spring Avenue intersection.

The new bridge has been designed to carry all truck loads and has a design life of between 75 and 100 years. The estimated construction cost for the project is $7 million.

tmorgan@projo.com