The scenery in Vikas' yard looks great! You could certainly do something similar with yours. Is there enough space to put a yard lead 18.25 inch radius parallel to the 20 inch radius main around the east end of the support column shelf? How much space is there from the fascia of the outside shelves to the north wall? (Assuming the door is at least 32 inches wide, there could be a minimum of somewhere close to 36 inches.) Would someone setting out a train on an arrival track be able to pass an operator sitting on a wheeled dentist's stool or chair, in order to stay with his train and uncouple his loco(s), and turn his loco or park it in an engine facility without interfering with the seated operator sorting cars from the east end lead into the classification tracks of the yard? How many cars do you plan to have in your trains (affects siding lengths along main, how many cars are available to be switched into/out of industries in a particular train, length of yards, length of yard leads; also number of locos needed to pull cars up a helix of x percent grade). If you have a 2 percent grade and use 2 locos, you probably will be able to consistently run 12 to 15 car trains and up to 20 cars with 3 locos. What are your thoughts about number and types of trains to be run in an operation session? I suspect two trains at a time on the main will be the maximum until operators are more experienced. And, if most jobs are designed to take between 15 to 30 minutes, you might be able to run 4 or 5 mainline trains in an hour. A third operator could work the yards outside the support column shelf on both the upper and the lower level (one train out of each and one train into each 15-30 minutes later). How do these speculations of mine match your expectations? I think that, if you have 4 classification yard tracks, 1 arrival track and 1 departure track, and 1 running track (or a main?) separate from a yard lead, plus aisle space for an operator with an arriving/departing train to pass while a seated operator is working the yard, it would be possible to put most of the lower and upper level yards on the outside of the support column shelves (as in your post above) with engine facilities and other yard elements on the inside. Or you could leave the backdrop out on the west end of the lower level, run the yard lead "through" the partition and along the west wall, and have all the turnouts to the classification and arr-dep tracks within sight and reach on the outside of the support column shelf at the west end of the yard. The turntable and engine facility would be at the east end of the yard (but NOT at the end of classification tracks, as Vikas' was), and trains would still come onto the arrival track in the yard from around the east end of the support column shelf.