I think you can get most of the benefits just from a well designed timetable. I get the impression that's mostly how they make it work so well in Japan. There

I think you can get most of the benefits just from a well designed timetable. I get the impression that's mostly how they make it work so well in Japan. There tend to be at least local and express services on almost all routes, and often multiple tiers of express. Another common pattern I've seen is having several commuter services which each run stopping for a different section of the route, and then run express to the central stations. This gives passengers the benefits of swapping between local and express services, without them loosing time changing trains. Of course, all of this is a lot easier when you already have the passenger numbers to support it.