What is "viewliner"

The Viewliner is a single-level car type used by Amtrak on most long-distance routes operating east of Chicago. With the exception of a prototype dining car named "Indianapolis", all cars which have been in service so far are sleeping cars and are assigned names that include the word "View." Amtrak began placing 130 additional cars into service on March 23, 2015, including diners, sleepers, baggage-dorms, and baggage cars.