I had another 3 APA boxes in addition to the one I used for Gn15, but did not want to build more modules.
I was wondering which of my scale/gauge combinations to use, but prefered to use 16.5mm gauge.
Not wanting to model OO standard gauge(or French HO) , I had choice of 1/12th scale or 1/35/1/32 scale. I chose the latter as I am also building a single 3ft by 2ft 1/12th scale layout, using bits from other modules.
Anyway 1/35 or 1/32 it was, depending on what stock runs.
There has been some discussion about circular layouts using the APA boxes, and I estimated a quarter circle of 2nd radius OO track(17.5in) would fit, and it does .
This would mean 3 boxes equal 3/4 circle and initially intended to use straight connecting tracks, but curved ones would complete even more of the circle. As Setrack points are 2nd radius I could easily include some pointwork. A bit more limited than what I fitted in my Gn15 module but creating a circle makes up for that.
Next question was where to put mouseholes.
If at each end then a short piece of straight track needs to be added, no problem.
I tried out having one hole in end and one in back and this nicely fits. It also changes the way you look at the track as it is not symmetrical.
I am planning to have central module with holes at each end, and each of the others with one hole in back panel . I hope this will give a pleasing overall look, which is neither flat nor too square.
One side module il have points to sidings/fiddle yard, and a point in back curves will allow trains to enter/exit in opposite direction. In practice trains will probably be allowed to go round and round, but it ill be possible to switch trains easily( an idea I copied from a friends On30 layout.
In some ways I wish I had thought of this design before building the Gn15 modules as it would have made the design more flexible, allowing both straight and circular setup, but I am not planning to change them now.