Here's some more info on the Gumstump and Snowshoe:
http://carendt.us/scrapbook/page38a/index.html
A couple of notes to keep in mind (I'm building mine in HOn3 myself):
- It's really a self-contained operation. I couldn't figure out any way to operationally incorporate the plan into a bigger layout other than as an independently operated branch or company. You would then logically run an interchange with the main railroad at the lower terminal - in my case a narrow to standard gauge transfer facility.
- By carefully controlling the capacity of each track (or setting useable limits during operation) you can have an Inglenook switching puzzle at the lower terminal. See the micro-layout web site cited for details.
- Realize that the lower track climbing to mid-level is immediately behind the next higher level of track, and is virtually inaccessible. This section of track must be bullet-proof, because there is no room for the hand of God to reach in there to rerail a derailed car or engine. Good thing the turnouts at either end of this section are accessible, or I would have to turn this plan down.
The rest of my notes apply to any similar shelf switchback design.
- As designed, the G&S takes 2 locomotives to operate. Any switchback layout that has spurs facing opposite directions at the upper and lower terminals works the same way. Some have added runaround tracks at either terminal (or both), which eliminates the requirement for the second locomotive.
-Train length and tail track length needs to be carefully considered. Iain Rice has written that the maximum length train that looks good on a shelf layout is 1/4 to 1/3 the shelf length, which makes sense to me. Train length is going to be limited by your shortest tail track, so there is little sense in making any of the other switchback tails longer without extenuating circumstance. Also, by extension, a tail track that holds engine plus 2 3/4 cars wastes space over one that holds engine plus 2 cars plus 1 inch for good measure. You have to know in advance how long your engines and cars are.
- Smooth vertical transitions are critical to the switchback grades. The vertical transition is more important to smooth operation than the percentage of grade, especially when using geared locomotives. Decent transitions will make the peak grade steeper, but will pay off in the train staying coupled and on the rails. I recommend making a cardboard template cut to your minimum vertical radius or transistion profile to check your roadbed against. I have to get this right before I lay any track! Some more knowledgeable than I have said the vertical radius should not be less than the minimum horizontal radius, and that that should be 4 times the longest car length for looks and operation. For 40 ft HO cars, that means 24in radius in both horizontal and vertical. That seems too conservative for my tastes, but it does guarantee good coupler operation, even on curves. The standard I am going to try is eased 15inch radius (for up to 36ft cars with MT N couplers) both horizontally and vertically. I may try to run a 50ft combine for passenger service or as part of a mixed train. Not sure whether the 50ft combine will work with this standard; need to run some tests before I commit. Having a proposed standard in mind also helps me during construction of my kit Shay.
