Southern Pacific 4460 is the only surviving class "GS-6" steam locomotive, together with "GS-4" class Southern Pacific 4449, which is operational in excursion service. The GS-6 is a semi-streamlined 4-8-4 "Northern" type steam locomotive. GS stands for "Golden State" or "General Service". The locomotive was built by the Lima Locomotive Works (LLW) for the Southern Pacific Railroad (SP) in 1943. The GS-6 lacked side skirting and red and orange "Daylight" paint found on previous locomotives of the GS class and were painted black and silver instead. The War Production Board controlled locomotive manufacturers during World War II and had turned down Southern Pacific's order of fourteen new Daylight locomotives in 1942. Southern Pacific re-designed the new fleet based on the older GS-2s, only with 260 psi instead of 300 psi, an all-weather cab, and a new GS-4 style tender. The design was finally approved, but the War Production Board reassigned four to the smaller and power-starved Western Pacific Railroad (only the tender from Western Pacific GS6/64 #484 remains). Their smaller size when compared to previous GS class locomotives and the fact that they were built during World War II earned them the nicknames "War Babies".