The Amtrak Sleeping Car fleet consists of two types of cars: Superliner and Viewliner. The primary difference is that a Superliner features two levels of private accommodations per car (double-decker trains) and Viewliner features a single level. For your trip, the type of car will depend on the route you select. Typically the Superliner trains operate west of the Mississippi River while generally, the Viewliner equipment operates east of the Mississippi River.