I really like the freight aspect of modeling and had a short discussion concerning the limited shunting operations in modern JR systems. My thoughts were to operate the yard based on maintenance activities and shunting of private cargo cars. I have been building my freight inventory based on this concept. One unit that I like is M250 Super Rail Cargo.
The M250 series caught my eye instantly with its impressive and unique appeal. Its a night runner from Tokyo to Osaka that run about 70mph (110km/h) Top speed is 130km/h. Because it is designed around passenger train specifications it can operate with passenger trains. This is kinda funny seeing a mule run pass a carriage.
http://www.youtube.com/v/oRZHzKHI5_gNow back to the point
Today, I ran across a few images that supports the maintenance concept.

I think there may be a lot more to do then I first thought. You can switch the M250 because Sagawa has 2 operating units 16 each with 10 spare cars. I'm sure that they rotate them around between runs. So, I think I'm on the right track <---- Hey that's a pun.
Bernard was going in the direction I want to go, although he is light years ahead it is the general direction just the same. I want to focus on a central yard with via duct/bullet train operating around it. I'm getting all the concepts, methods and pieces together. (Hence the cantenary and station thread, I'm learning as I go and its slow) hopefully I can get it all together and start soon.
Here is the conceptual layout, lot of pieces laying around but a general concept. Oh, this is Kato #611 layout modified/hacked up. Will have entry and exit into the yard. 24" grid
Inobu