A Challenge: Designing A new modular layout section

[Sumpter250]

As for the "main" line if these are to be paired modules the only place you would really need the 9" centers would be at the extreme ends of the module set.

I have to ask the same question, which begs the next question - - - would your "two module SET" ever have to be separated, and placed in different locations ?

Because both of my three module sets, are a single scene, they are always considered " one long module ", and, in fact, the two track main "separation" of two inches, has to vary to accommodate the spacing of the bridges. I do have to adhere to the minimum radius specifications for any mainline track, but could move the interface points of the center module, and the inner end points of the adjoining modules, to allow some variation within "the scene".
( I don't, but I could ) Maybe it's a question you should ask of the group, just to see how much leeway you could have.