The automotive manufacturers General Motors and Chrysler were partially nationalized in the wake of the 2008 Financial Crisis as were several banks… these were less a full government takeover and more of a government guided restructuring. Before that, the only full nationalization of anything substantial was the bankruptcy of the Penn Central Railroad and subsequent establishment of the US’s only national freight rail company in ConRail. It was later privatized and is now the private companies CSX and Norfolk Southern. The collapse of Penn Central was the largest bankruptcy in history until Enron in the 1990’s. Amtrak, our national passenger rail corporation, is also a nationalized entity created around the same time as ConRail, for similar reasons, and is still nationalized (although the Trump admin wants to privatize it).