There are a lot of designs on the web for micro layouts; many of them are in HO, N, and Z, and I'd say 3/4 of them are narrow gauge. If, however, you define a "micro" layout as any layout that is 4 square ft. or under in area, I have created a track plan using standard Ross Custom Switches pieces that allows you to run those 2 foot-long autoracks or really cool Lionel 86' auto parts boxcars in a micro layout's footprint.
A few measurement things to note:
I measured the layout's length and width with SCARM's tape measure tool, so I can't give an ironclad guarantee that the length and width measurements are accurate. Additionally. I measured it from the ends of the crossties, so the track will run right at the edge of your baseboard.
The layout is roughly 8 feet long by 6 inches (1/2 foot) wide. The track plan itself is fairly simple, with two parallel sidings connected by a pair of RCS 11-degree turnouts. The key to operating the layout (aside from using a small engine like a Lionel Trackmobile or K-Line Plymouth), is what occurs under the big gray structure on the right side of the above pictures. The track closest to the backdrop (the big blue square) under the gray building is the staging track. Here, cars are inserted and removed from the layout via the operator's hand or a car-lift that descends under the layout. Additionally, by removing a car and then running the switcher through the building, the operator can run around the car without a run-around track (or just use two locomotives).
The siding on the right that is closest to the edge of the layout is the auto plant siding. Here, up to two scale modern autoracks or 89' boxcars can be stored. The operator must come up with a creative method to get one of both cars out of the plant, however, since the switching lead can only accommodate one car and the locomotive.
The other long siding (in the back left corner of the layout) has various uses. It can be used as another lead track to facilitate easier switching of the auto plant. Or, to add an additional layer of complexity and variety to switching operations, the siding can be used for additional industries, perhaps even an auto parts manufacturer so as to provide another place to switch those 86' boxcars.
For one final twist, there is a grade crossing in front of the auto plant that cannot be blocked by a standing car.
This plan is not perfect, but I believe it is one of the few micro layout plans in O gauge that allow the usage of such big cars. If anyone ever decides to construct this layout, I would be very interested in seeing how it turns out and how you operate it. My email is in my profile.
I am NOT charging for this plan (the SCARM file is included), but I would very appreciate (if you ever make this plan) that you do not adopt this idea as your own. Basically, don't plagiarize.
Thanks for bearing through this long post. I hope you enjoyed it.