Are you talking about Conrail? Because Conrail was created because the private railway system was collapsing due to mismanagement, and many railroad companies

Are you talking about Conrail? Because Conrail was created because the private railway system was collapsing due to mismanagement, and many railroad companies were going bankrupt. After nationalization Conrail quickly turned into a huge success, and was sold off to private investors after a decade for a massive profit. If anything, privatization was the best thing that had happened to the railways in decades. And that's not exactly a one-time-thing only - the railways were previously also nationalized during WWI, which had a similar success.