I got 4 locos (GP9, GP30, GP35, H-15-44) and about 20-30 freight cars, but I only use maybe 3-4 most of the time. They have knucle couplers, while the others have rapidoes (i know, I know). 2 locos have knucle couplers on front, and rapidoes in back. My newer Geeps have both ends w/ knucles.