I'm thinking about getting http://www.walthers.com/exec/productinfo/933-3204 , however I need to know if it will fit the existing tracks I plan to put it over. The 2 track siding usues the standard atlas switch with the included curve to make it parralel http://www.walthers.com/exec/productinfo/150-2702 . I assume it will fit since the outline demenions seemed to fit fine over the area, and it was probally designed for this arrangement. Can anyone who has one of these clarify for me?