This opulent grand stairway was home to the great/choir division of the organ.  The echo division was some four stories above, residing at the top of the elevator shaft.  The location of the console is not known.  In the basement, the swell division occupied a tool room, and the sound was ported up to the main floor.

Even this black and white photo reveals the elegant detail of the main stairway.  Parquet floors give way to a carpeted staircase featuring many wood species in the railing and balusters.  One assumes that the large newel post lamp is covered with a Tiffany shade