The Superb was used as U.S. President Warren G. Harding's personal Pullman railroad car in a cross-country tour in 1923. After Harding's death, the car returned his body from San Francisco to Washington, D.C.. Built in 1911, it is the second oldest steel private car in existence. It had previously been used by Woodrow Wilson. In 1926 it was temporarily renamed Pope Pius XI for the Cardinal's Train from New York to Chicago. Later it was an office car for the Charleston and West Carolina, Atlantic Coast Line and Seaboard Coast Line railroads.
The car is presently located at the Southeastern Railway Museum in Duluth, Georgia.