It will start out as all newer engines and then expand into older ones as it will also be a collection of Milwaukee Road engines. I don't have my planned roster list but if I remember correctly I want to start out with AC4400, SD60M, SD70MAC, and FP45 (for special excursion trains) for 6-axles, and Dash 8-40BW, B30 or 36-7, and GP15 for 4-axles. I plan to have enough engines to back date so SD45-2, SD40-2 , GP40-2, GP38-2, SW1200/1500, and possibly GP30 will be making appearances. I'm also thinking of maybe making a more modern shuttle service using a Dash 8-32BWH for motive power/HEP, and am track cars painted to resemble the old Hiawatha cars and call the Hiawathan. I'm still stuck on using a single track helix or possibly a doubl track helix so I can have one track as storage. Will also have one or two hidden staging tracks on each level so I have a spot to park the pulp wood cars and hopper cars off scene. I have some info on modeling a pulp wood mill and it seems that just this will provide alot of switching and such, but I think I also might want to have e concrete/cement plant.
I did look though and the one helix I was thinking of was made by Ashlin, but I can't really get much info on it, like how many tracks, the radii of the track. All I could really find is it will be a 15 inch rise and about 3 feet across. I really don't want to give up that much room for it, the layout will be tucked in a corner with a small L leg to connect to the helix so I can use the full 8 feet length available.
If you can draw a circle on plywood you can lay out your own helix.
First, determine the minimum radius curve you can handle, based on the rolling stock in your roster plus any planned acquisitions.
Then determine clearances. Unless you are planning to run something really odd, one inch on either side of the centerline is probably overkill. OTOH, if you use threaded rods to support the roadbed, the clearance should allow for them - and the shape might more closely resemble something with flat sides instead of smooth circular curves. Minimum vertical clearance between levels should, ideally, give room enough to get normal-size human fingers to the site of any problem without resulting in an excessive grade.
The easy way to build is from the bottom up, adding the higher levels after laying and tweaking all the track that will be covered over. Tracklaying on a helix is one place where it will pay to make haste slowly, because it will be a thundering PITA to go back in to do it over.
I actually model in twice-N scale (1:80, aka HOj) but the basic principles apply to all scales. The helix I'm working on has a 350mm radius (about 14 inches - close to the size you need for longer N-scale rolling stock) and rises 3.25 inches/turn - about 3.5%. The basic structure is a 12-sided trough of steel stud material, which leaves plenty of clearance for support at the outside angles and half way along the inside flats. If I was modeling N scale, the rise per turn could be reduced by about 0.75 inches and the grade to less than 3%
Chuck (Modeling Central Japan in September, 1964)
Excellent Helix Plans in May/June 2003 N-RAILROADING By Paul Petrzelka. He uses 1/2 plywood risers. I am using 1/4" ready rod with nuts& lock washers. Pretty darn hard to go wrong.
Jacobo
Is there anyone out there who makes N scale helixes Besides Ashlin Design? They want 180 bucks for a double track, which doesn't seem bad, but still too much for me. I think it was the last MR issue had a quick new products thing at the back about a helix but it was only like 120 bucks, way cheaper. Of course I keep forgeting to get the web site for more info. I only need a single track and has to allow anything from a switcher to a big 6-axle diesel, and long cars like 70 foot center beams, but it also has to take up as little horizontal space as possible. I know building it myself would be hecka cheaper, but judging from the past I'm not the most accurate when it comes to measuring/cuting wood. In shop class I also seemed to be a hair off, and I know in something like a helix a hair off can be the difference between running great and having your rolling stock go for a 5 foot sky dive with out a parachute. I know MR did an article on making one I do believe April '08 issue, and I will be rereading this article tonight. If I remember right it was complicated enough to make the measurements, and like I said I know they have to friggen accurate to with in a hairs width so-to-speak. More than I think I want to chew at one time. Thanks for any helpsies.