run arounds

I would argue that the runarounds performed within the two blue yards aren't strictly necessary when they could back their existing cars onto the pickups if they needed, but that sorta falls under the category of "more than one way to skin a cat" and quibbling with really minor details...

But a really great overview of how cars connect from one train to another.

Reciprocal vs. Trackage rights

One thing that modelers always seem to want to do is to grant "trackage rights" to other railroads so they can have multiple railroads switching their industries.  Prior to the 1980's that sort of thing was almost unheard of.   In most cases (even after the 1980's) reciprocal switching was a much, much more common way for two railroads to serve a customer. 

And trackage right does not automatically mean that the tenant railroad can serve any of the host railroad' industries.  In most cases, railroads with trackage rights are specifically forbidden from serving local customers.  If the tenant railroad does serve local customers on the host, there are often very specific restrictions on where the traffic can originate or terminate.

The caveat about the 1980's is that's when the really big mega mergers started happening and as a concession to the merger, the ICC/STB required the merging roads to grant another railroad access to serve industries where both the merging railroads could serve industries (2 to 1 locations).