The dome cars when built did not have those Fins (ribs) as everyone has called them. The railroad added these so called airfoils to roofs infront of the domes a couple of years later,their purpose to keep dust /snow from collecting on the front dome windows (windshields) .Kato's cars are correct for as delivered in 1955,early PR & Builders Photos show no fins. The fins were not entirely successful, when cars were re sold other owners removed them. UP on the other hand when they bought back two more dome lounge cars added fins to what would be the rear roof behind the dome on their two cars out of three that are still configured for mid train service since they have been run facing in either direction on special trains. The car configured back to a rear end car "City of San Frabcisco" is not done this way. The Overland Brass Heritage Fleet models have the Fins in the Correct Locations as the cars are presently configured. Nate Goodman (Nato). Salt Lake, Utah.
