Heh. I'd probably recommend TS12 simply because I don't know what I'd do without three routes to run:
-Rollins Pass NG(Not too many industries but man is it fun! And the route is built to exceptional standards)
-Foxshire Light Railway(One of
's creations, it started as a testing route but is by far the best of his 4x8 series. It feels like a real line, and he has plans to expand it to include a slate quarry and a dock, which will make it even more fun)
-Freeport & Waterford Mills(Never actually completed but a beta went out at Christmas, the completed route will be quite epic indeed considering the caliber of the beta)
And the Durango & Silverton looks nice; however I haven't run it yet due to having ~30 missing dependencies.
Not to mention projects underway:
-Colusa & Lake Railway(A California Narrow Gauge line in its entirety, most of it is straight but the scenery up near Sites is to die for! Beta should be quite near)
-Ffestiniog & Welsh Highland Railways(This thing is a huge, extended project. I do not know when it will be complete but screenshots look absolutely stunning)
-Donner Pass(modern day, but I heard rumors at some point that Jango has a historical one planned if he can find enough data)
-White Pass & Yukon(just started so this one may be a couple years in the making but it'll certainly be epic)