I haven't noticed any mention of the overall room size, but a 24" shelf offers plenty of room for industries, both large and small. While much of my layout is about 30" deep, it's similar in concept to your plan of a single-tracked main with passing sidings.Almost any Walthers structure kit can be modified for a shelf-type layout by utilising the unseen back wall to extend the visible one, and where space is tight due to aisle-side industries, the end walls can be shortened or eliminated entirely. (And don't discard the leftover pieces - they can be combined with other cast-offs to create another industry.)
Here's a good choice for displaying and using those reefers - Walthers ice house with add-on platforms. While the layout here is about 42" deep, I'll have only two industries here, and both could be used on a 24" wide shelf, either end-to-end or, with some modification of the latter one, with one in front of the other.
The curtain wall factory in the rear was made from parts of two Walthers stamping plants, along with some leftovers from a kitbash of their George Roberts Printing factory. All of the long walls are used on the side visible from the aisle, while the end walls can be used as-is or shortened or eliminated completely. The unseen rear wall (needed for structural integrity on anything deeper than a "flat") is plain .060" sheet styrene - it's available in 4'x8' sheets from any plastic supplier at a reasonable cost. It's also useful for making larger roofs and for foundations, too, which can change the appearance of many common kits.
Another Walthers kit suitable for a shelf is their Vulcan Foundry. Again, the unseen rear wall is plain .060" styrene, and that wall was used to double the length of the structure. I added some MDC wall sections and a modified LifeLike Bottling Plant to enlarge things further, but they could be eliminated. If you wish to decrease the structure's depth, cut the end walls at a point either behind the cupola or at a point on the rear slope of the cupola's roof - this will impart a more three-dimensional appearance than if the cuts were made at the end of a plane.
Here's another one from Walthers, and ideal for a shelf layout, either as-is or with the end walls shortened. This is two Waterfront Warehouses, with roof and rear wall of plain styrene. I modified the one visible end wall to include a ground-level street front, as the building is rail-served on an elevated right-of-way:
The shelf here is only 21" wide, but it includes a double track main, three industrial sidings, and a long siding for interchange car storage. It also includes a large industry which generates enormous amounts of traffic. It's built from Walthers' ADM Grain Elevator kit, along with the add-on siloes and Redwing Milling, plus several scratchbuilt portions using more .060" sheet styrene. The kits are, naturally, re-arranged to suit the narrow shelf, and I've placed them at an angle to avoid the "flat against the backdrop look":
Here's a view from the opposite end:
Don't let the description on the box limit your use of a structure kit - if you like the looks of it, build it as intended or modify it to suit, then create signs to make it into an industry useful for your layout.
Wayne
Someone mentioned the room dimensions. The second floor of my home is basically 3 rooms, each 13.5'x13.5' arranged in an L. I'm using two of the rooms with trains passing thru the wall between them twice. This is where I get the 13.5'x27' I mentioned in my earlier post. I will be starting a build thread as soon as I have enough to warrant a picture