My only comment about dual mains is that they don’t need to be parallel around the entire layout. Obviously they need to be at the bridge and crossovers, everywhere else they can meander, go over/under, etc.
And crossovers don’t need to be close to each other either.
The wrinkle I see is the subway and I’m still not sure how that’s going to run. I assume it will eventually run close to the edge on a shelf with viewing stations at various points. It’s hard to design the run though without knowing what the min curve size needs to be, etc. if you hide most of it, it’s just a waste of track and money.
Thanks for the dual mains help and tips, same with crossovers. The subway will run close to the edge on a shelf with station stops along the way. At one point I hope it will elevate to main level for the last stop. I am not sure how and if that will work at all, however this is the dreaming stage. As far as a waste of track and money, well I can not argue that at all at this point. It will be the last part of the build and if funding runs out then so be it.
Thanks again for all your help!