To get started....I would reserve a large area! I had a Bowser 32" and a Korber 5 stall Roundhouse.
An area 72" x 96" is a good starting point. The large Turntable, whisker tracks and the Roundhouse (assuming you want the rear extensions for the big guys) will quickly eat up 80" to 85". That does not include any lead tracks into the table. Where many folks "mis-calculate" is the area (length) required from the turntable to the Roundhouse to get the required angle to hit all the Roundhouse doors at their midpoint and then "fan out" into the building on a straight tangent. All of this is dependent on the brand of Roundhouse you plan to purchase.
If you are going with ROSS, I would give Steve a call and discuss with him your dimensional requirements. Steve is a good guy to work with.
Here are a few pics from my old layout. Good luck. Let us know what you decided.
Donald
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