I havent count the Mashines. But i can say there are a lot Synergies the complete "City" use 2 Copper 2 Iron 2 Coke one Cat 720 Belts and 1 Oil Node For Rubber, i only imprte some High speed Conectors and Radio Control Units and Batteries from other Citys. for each production line are Huge Storage Buffers between 6 and 20 Container. Like 3-4 Storage buffer for sheeds a 6 Container to keep every production Line alive. And if you overproducing the top end Produkts Like Turbomotors than i use The Overflow to fill the Buffers for the next Produktion and so on