06-21-2010, 09:24 AM
nachoman Wrote:It entirely depends on what kind of equipment you are running. If it is 4 axle diesels and 40-50 foot cars, I foresee no problems with those curves or grades. Even most 6-axle diesels or 8-coupled steam engines won't have problems with 22" curves if you take it slow. A lightweight 0-6-0 may not be able to handle 8 cars on that grade.
If you are putting it in a closet, you almost have to build it before you build the layout, because once the layout is in place you may no longer have access to the closet. Trying to shoehorn a helix into a closet with access blocked by a layout could prove extremely frustrating if not impossible.
I had forgotten about the access issue. You will need to be able to crawl under and come up in the middle of the helix to rerail rolling stock that derails in the helix. You will need some sort of barrier on either side of the helix to keep your trains from taking the big drop to the floor in case of a derail. Your radius is always measured to the center line of the track. That means that your maximum size hole to come up through will be 20 inch diameter. If your shoulders are wider than 20 inches, you can only get your head and one arm up there to rerail. At best it will be awkward if any problems occur with the train, at worst it will be impossible. I think that if you don't have space in that closet for more than a 22 inch diameter helix, it won't work. Your absolute minimum radius for a helix has to be the width of your shoulders + a couple of inches when there are walls around the outside of the helix.