The Port Authority of New York and New Jersey approved spending about $300 million to replace a 106-year-old swing bridge over the Hackensack River that often triggers train delays through the region, as part of a $24 billion project to improve rail access to New York City. The Port Authority agreed to pay principal and interest payments on a federal loan to replace the Portal Bridge with a fixed bridge with higher clearance. About 450 New Jersey Transit and Amtrak trains cross the bridge every weekday. Frequent mechanical failure causes delays for tens of thousands of passengers, said Port Authority Executive Director Patrick Foye. “Today’s commitment is an important early step,” Foye said. The new bridge will cost more than $1 billion. The U.S. Department of Transportation, New Jersey Transit and Amtrak will also contribute funding, Foye said. Construction of the new bridge is expected to begin in 2018, he said. Interest payments on the loan will begin five years after the new bridge is completed in 2022 or 2023, Foye said. The $23.9 billion Gateway project includes the construction of a new rail tunnel under the Hudson River and the rehabilitation of the existing century-old tunnel, which was damaged by Superstorm Sandy. About 200,000 people daily travel through the existing tunnel, which has less than 20 years of service left. The program will be funded half by the federal government and half by the states of New York and New Jersey.