07-20-2009, 10:53 PM
Russ Bellinis Wrote:Josh, the radius of a helix not only allows for the use of long equipment, but also allows for reasonable grades. You probably need about 3.5-4 inches from the rail top to the bottom of the next level of the helix. You don't need road bed on a hidden helix, but you will need it to be strong enough not to flex. If it is made of 1/2 inch plywood, with 1/4 inch allowed for the rails, you are looking at going up 4 3/4 inches in each revolution of the helix. If I have figured the math correctly, you are looking at slightly more than a 3% grade, but you are going to tie up a space of nearly 48 x 48 inches for the helix. An alternative might be to put Modesto Yard on an "elevator" traversing between the 2 levels of the layout.
Great advise Russ, thanks for your reply
The longest equipment i would be running in my trains would be 60' cars. I dont anticipate on running 72' Centerbeams, 89' Auto Carriers, Double Stacks besides in the yard and in the Transload Facility and maybe to a couple businesses along the left side of the layout which would be on the top level. There for they would not need to go onto the lower level.... I would however like decent spacing between the 2 levels. im not sure, but i think 12-14" between the top and bottom levels would be good. Any opinions on level spacing?
Im not the best at math, and im going to need some help with the creation of the grades and such on the helix... lol. I wouldnt mind having a 3% grade on the helix. Ill be running three or four 70 Tonners, 2 SW1200's or 2 Gensets, which should be enough power to tackle the grade. Obviously a grade less then 3% would be the best, but i dont think its a must... Opinions are welcome on this as well