Here is a shot of the first scene I am working on snatched from the Pacific Electric Railway Historic site.  Called the Chatsworth Spur it was a pair of packing plants that were located right off Brand Avenue towards the middle of the line.  As with Bruce's design, this will be the anchor module and to the right will be a removeable section that will serve as staging track and room to  move cars back and forth.  I joined two modules together to get the correct shape, a funky corner piece with a wedge taken out and a 4'x14" straight section welded to one side.  As it happens, two parts designed for another section worked out well for this application.  

Showcase Minatures makes an HO half model of the wood sided building to the right. Showcase  As it happenes this kit will almost fit the area I have maped out, but will instead scratchbuild my own to save time and money.  The one on the left is unique and there are only a few photo's of it I could find on a google search.  Enough to get the concept down and make something.  As with any modeling, eventually you are faced with proto/fantasy and near enough, or build something else.  This will be a cool scene expecially with the large tree out front, the double street crossing and the busy details in the yard.