Operating Era: 1905-1970. Southern Pacific, Galveston, Harrisburg and San Antonio, Houston & Texas Central, Union Pacific, North Western Pacific, Southern Pacific de Mexico, Texas & New Orleans. The Harriman roads were producing standard designs for stock cars since 1905. The S-40-4 was the first design to incorporate a straight side sill. Before production ended with the S-40-10 over 6,300 of the design were built for Southern Pacific, Union Pacific and their subsidiaries. Many cars ran into the 1960's. The spotting features on the S-40-5 are the single I-beam Bettendorf center sill and the feed door on the B end.. SP used the design up into the 1920's. The only class it didn't have was the -6 which was identical to the -4 except for the center sill. Instead, it had the -5 which had no feed door on the B end. Other than upgrading to AB brakes and revising the size of the placard board in the 1940's the cars ran into the 1960's virtually unchanged. Our kits model each class with K brakes and decals covering the life of the car for SP and its more common subsidiaries. Now includes our new One-Piece Roof Frame.