The plan all along has been to work this little layout for two eras or more. Late 1970's and late 1980's for sure, with maybe a late 90's thrown in now and then. The area I'm modeling stayed roughly the same during this time. The only distinctive change was 1986 when C&NW sold it's Winona, MN to Rapid City, SD line to a group of investors who started DM&E. At that time DM&E didn't have any rolling stock of their own and relied on a lease agreement with C&NW. DM&E did get several locomotives from C&NW, and bought several more from SOO. To pull off my dual era all I need is a change in locomotives. For the C&NW roster an array of beat up Alcos will make it clear we're looking at the end of an era, and for DM&E a couple of raggedy SD9s and 10s should be enough indicate the beginning of another. The DM&E will also roster an SD40-2 in new blue and yellow paint.
The C&NW roster shouldn't have any problem negotiating the tight curves planned. The problem comes when I skip ahead 10 years and try to run the DM&E Severe Duty power. The SD9 and 10 might negotiate the 9 3/4" curve and tight #4s in the staging yard, but I'm fairly certain the SD40-2 isn't going to like that and now is the time to do something about it. At best it will probably pull the car behind it off, and at worst the whole train will flop off the rails and onto the floor. This saddens me a bit, because I had intended to lay all the track using stuff I already have, some of it from my first trainset. Something's got to give though, and unfortunately this track is out.
Pulling the plug on trying to build this without buying any track means there is a great deal more flexibility in how the plan can come together. The new plan features 12 1/2" and 13 3/4 for the two big turns and 15" for the S to the elevator tracks. Not large by any means, but way bigger than 9 3/4 and big enough the SD40-2 should be able to make it through with cars in tow.
Those large curves eat up a lot of space, no longer a 30"x80" it has been stretched out to 36"x96". It is amazing how much more railroad can fit with just a few more sq.ft. The return of the switchback is unfortunate, but not a show stopper. I anticipate the elevator switch engine will be parked somewhere along the spur to the right. The road power will deliver cars to the elevator in 3-4 car cuts and it will be up to the elevator crew to get them all spotted under the loader. That operating change should make the switchback be less cumbersome. The road power won't ever be zig zagging through it, and the elevator switcher won't ever leave it. The angle of the switchback spur is open to debate, it doesn't look right as is. Staging capacity has been increased by a car length or so, and new to the plan is a locomotive staging yard. I think my favorite change is the flowing mainline vs the Bowman Gray stadium.
I still have all the new track I bought for my attempt at a shelf switching layout, but quite a bit more will be needed. Thankfully the Atlas Track Famine has passed and I should have no problem locating the rest of it. Cost will be an issue however, as I've gone from having near zero cost for track to several hundred dollars of track. Because if this I've decided to break it down into more affordable chunks. The main loop will be laid, followed by the industry spurs and interchange, and finally the staging yards. The main loop is key, because getting it to a point where trains can run, even if just a loop, is a huge motivator.