Rivarossi HO 1253 4-6-6-4 Challenger '3975' - Clark Railworks,Rivarossi 4-6-6-4 Challenger Union Pacific 3979 HO scale,Rivarossi HR2385 - Italian steam locomotive Gr741 205 of the FS; with 3 axle tender, DC Digital with Sound,Rivarossi,Jaap Horst History of Technology page: Rivarossi Challenger locomotive of the Union Pacific Railroad company,