FDR used US Car Number 1 publicly but there is also another railcar he used privately and it is still underneath a New York city hotel..........,(reply>), I remember seeing that on a prime time documentary show that got several things ridiculously wrong. The reporting marks ended in X, denoting a non-railroad owner, but the show stated that it meant government ownership. They also speculated that the clerestory roof openings might have been used as "gun ports".