Northern Pacific Passenger Car

These passenger cars are painted in a faded blue scheme that the Great Northern or Amtrak commonly used during later service years. The vehicle closest to the camera is marked GTLX 203, which indicates that it was later reclassified under private or leasing ownership, likely after Amtrak or for maintenance-of-way or special service. 

I am not sure the specifics of these cars, but in general, these cars are streamlined, lightweight, stainless-steel cars, originally built in the mid-20th century—typically by manufacturers such as Budd, Pullman-Standard, or ACF—for long-distance passenger service. Designed for comfort at speed, they featured air conditioning, reclining seats or sleeping compartments, and were often used in premier trains like the Empire Builder or North Coast Limited.