Two lanes of roadway beneath a 100-year-old East Baltimore rail bridge remained closed Monday after a chunk of concrete fell from it the previous day, but Amtrak stressed the span was “structurally sound.”

The concrete chunk fell and struck a passing SUV on Sunday, sending the driver to the hospital with non-life threatening injuries and raising questions about the bridge’s structural integrity.

The underside of the bridge has so many nicks and cracks that it’s tough to determine where the chunk may have fallen from — steel rebar protrudes from concrete that appears to have been chipped away over the years, perhaps by passing trucks. Photos from the scene show that the fallen chunk may have struck the driver-side windshield of the navy blue Ford SUV.

As of Monday, the two westbound lanes of North Point Road underneath the bridge remained closed to traffic, and the eastbound lanes had been altered for two-way traffic with one lane in each direction. Drivers were advised to expect some delays.

The concrete bridge, embossed with the numbers “1927″ for the year it was built, is owned by Amtrak. . The federally subsidized passenger rail company is investing billions of dollars in Maryland to build a new tunnel and in a slew of other improvements thanks to ambitious spending approved during the Biden administration. But there’s clearly more to be done to make the state’s rail infrastructure more resilient.

This rail bridge and a parallel one owned by freight company Norfolk Southern span a section of North Point Road just west of Interstate 95. It’s a through-truck route and notorious for flooding during heavy rains. Almost 1,800 trucks take it on an average weekday, according to state data, and the bridges have minimal clearance for trucks to safely pass under.

In an emailed statement, an Amtrak official wrote that the bridge is “structurally safe and sound for train traffic” and that bridges are inspected regularly.

With the help of federal grants, Amtrak is building a new West Baltimore tunnel to replace the Civil War-era B&P Tunnel, planning the replacement of a rail bridge over the Susquehanna River, revamping the historic Penn Station and replacing 100 miles of catenary wire between Baltimore and New Carrolton to power its trains. The modernization effort is just as active outside of the state, as the company contends with a huge portfolio of aging infrastructure.

It’s not just Amtrak that’s dealing with issues. The Howard Street Tunnel, which is owned and operated by freight company CSX Transportation, is more than 120 years old. CSX is in the midst of a massive project to enlarge the tunnel and lower the tracks to allow trains carrying doubled-stacked freight containers as the Port of Baltimore expands. They are replacing two rail bridges as part of the initiative, as well as modifying the bridge or track at nine other locations in the city.

The Maryland Transit Administration, which operates a Metro and light rail line as well as MARC commuter rail, has its own issues with aging train gear. Roughly a year ago this week, the agency shut down light rail service for two weeks in connection to botched rehabilitation work on its aging fleet of rail cars.