Transition from up grade to level?

Model Railroader Layouts and layout building
1

I have always wondered about the trick or formula for transitioning from an up or down grade to level track? Is there a formula or trick you guys use to figure out how long a transition track aught to be and at what % grade? I will be building a Helix with a 2.75% grade in HO. Any info would be greatly appreciated. Terry

2

I used a cookie cutter with 1/2 plywood. I placed the first support at twice the distance of the rest of the supports and allowed the plywood bend to create a parabolic curve. It worked quite well.

3

Chip - Tks for the info however I am not sure about the reference to the “Cookie Cutter”? I doubt seriously if my wifes cookie cutter would cut through 1/2 in plywood? I think I am missing something. Terry

4

The key is how much clearance your car or engine with the lowest to the rails profile. My first railroad almost forty years ago was to too steep a transition and as a kid I cut the pilot plates off an Athearn RDC so it wouldn’t scrape the rails during the transition. I would make the transition over an absolute minimum of 4’ in HO and possibly as much as 8’ if I had the room.

5

ndbprr - Thats what I was afraid of hitting the rails if I had it too short. So I guess based on how much room I have I should probably experiment and make it as long as practical watching the clearance of the steamers. Terry

6

Cookie cutting is cutting the plywood to the shape of the track and supporting it at various intervals to determine the height. I basically halved the grade for the first 12" and let the plywood tinsel properties create a smooth transition.

7

Hi Terry, I use 3/4" plywood for the subgrade (subroadbed) of my track. One of the reasons I like using material this thick is that it’s very hard to bend into a vertical curve that will cause trouble with even the longest HO scale equipment. At the top or bottom of any grade, I set one end of the plywood subgrade level and screw it in place, then set the other end to the grade (my steepest is 3 percent) and screw it in. The natural curve that forms in between works just fine. So long, Andy