Sadly the Cold War was a major cause of the failure of the US Railroad System. General Dwight Eisenhower spent a lot of time in Germany after WWII and saw the advantage of the Autobahn. When he became President he remembered of how the Nazis used the Autobahn to move troops and munitions efficiently. Railroads were easy to disable, roads on the other hand were not. In the event the cold war turned into a hot war, the government could nationalize the airlines and use the highway system to move troops and munitions where needed.