The National Transportation Safety Board says a cockpit voice recorder was not working on a medical transport plane that crashed in Philadelphia in January and likely had not been working for several years.

Critics say the patchwork system of safety regulations governing massive cargo ships like the one that toppled a Baltimore bridge this week can allow shippers to skirt oversight.

FILE - In this Jan. 1, 2021 file photo, The Amtrak Metropolitan Lounge overlooks the newly-completed Moynihan Train Hall in New York. Two major railroad workers unions have asked the Department of Homeland Security to beef up security on Amtrak and other passenger rail lines, including by creating a no-ride list akin to the no-fly list that prevents people identified as risks from boarding planes. – Two major railroad workers unions have asked the Department of Homeland Security to beef up security on Amtrak and other passenger lines, including by creating a no-ride list akin to the no-fly list that prevents people identified as risks from boarding planes. Ferguson, of SMART-TD, acknowledged there would be a cost to creating a no-ride list, but he said it should be minimal considering that officials would simply be sharing the existing no-fly list with railroads. The unions also asked the Federal Railroad Administration to require more security, but that agency declined to intervene Thursday because the Department of Homeland Security has jurisdiction over such matters.