Complex sentence: In addition to the 50 Sightseer Lounges, five lounge cars were converted from Superliner I dining cars for Auto Train service; these cars, which are only found in that train, lack the larger windows of the Sightseer Lounge cars.
Split into simpler sentences: In addition to the 50 Sightseer Lounges, five lounge cars were converted from Superliner I dining cars for Auto Train service. These cars, which are only found in that train, lack the larger windows of the Sightseer Lounge cars.