Hello I am new to ho model railroading. I have a 3% incline on a track going into the mountains. The grade also has a curve. I want to know how much or if an embankment will help. I have read that it would but don’t know how much of a bank I need? I am just trying to make it as easy as possible.I have heard of using masking tape layers to make the bank- is this the right way? Thanks for the Help Dave!
[#welcome] And welcome to the wonderful world of model railroad civil engineering.
If I am reading your post correctly, what you want to know about is superelevation (raising the outside rail on a curve to assist in turning.) An embankment (aka ‘fill’) is the dirt piled up under the ballast to raise track level above ground level.
Due to the really low 1:1 scale speed of our models (an HO passenger train zipping across country at 79 scale MPH is actually running at about 1/4 of a normal person’s walking speed) superelevation is purely cosmetic - but nothing says ‘well built railroad’ like a nice superelevated curve. There are several ways to raise the outer rail, layers of masking tape being one. I personally use card stock, but that’s because I lay my flex track on a full-size card stock template and have plenty of odd-size scraps available.
Superelevation the real way requires spiral easements. At the actual point of tangency there is no superelevation. Half way through the transition to curved track the superelevation will reach half height. Full superelevation starts at the actual point of curvature. For a model, four to six (scale) inches of height of the outside rail above the inside rail is plenty - more might cause problems. In HO, raising the outer ends of the ties about 3/32 of an inch looks good. The key is to make the rise gradual, not abrupt.
For much more, just enter superelevation and/or curve easements in the Search block to the right - and then settle back for a lot of reading.
Chuck (Modeling Central Japan in September, 1964 - with superelevated curves and spiral easements)
Yes, I agree. I have found, though, that superelevation can be overdone from the visual standpoint. It seems to look about right as you are inserting it, but later on you may find, to your dismay, that it looks quite a bit overdone in images taken head-on of trains midway through elevated curves. You might want to experiment a bit with tape or cardstock and take some images to find out where your eye offers the greatest approval. You may surprise yourself. Once you get a range of thicknesses that work best for your eye (and camera), then you can do the real work on your layout.
-Crandell
Thanks If I am understanding all of those big words correctly then I am on the right track. I am going to use layers of tape going from a layer of one increasing gradually to a layer of 7 or 8. Then gradually decreasing coming out of the curve. Thank You for the info Dave!
Chuck, I just wanted to highlight that line from your post above because I think it may get lost in everyone’s instructions (excellent tips, BTW), especially since it seems the original poster was thinking that the superelevation may help the performance of model trains on a steep, curvy grade. Jamie
Dave,
I’ve found strips of “1 by” (0.011" thick) and “2 by” (0.022" thick) dimensional styrene very handy for HO superelevation. I prefer the 8" wide stock so I purchase 1x 8 and 2 x 8 styrene.
What I do is to glue the strips to the underside of the rail ties using Testor (thin) plastic adhesive; parallel to and directly underneath the outside rail of the track. For flex track: Wait till the adhesive dries then use nippers to break the styrene between rail ties so that you can “flex” the track.
I wouldn’t go higher than 1/32" (0.031") for HO superelevation. Even though my layout is smallish (4 x 8), I have superelevated my mainline. Although the visual effect is subtle, it’s still noticeable and I think it adds to the realism of the layout.
Hope that helps…
Tom
It’s very easy to add superelevation if you’re using separate roadbed mounted on risers. I cut all of my curves out of 3/4" plywood, then spliced together pieces of the required radius until I had a section long enough for the curved area. Once the curved section was in place and fastened to the tangents at both ends, risers were fastened to the bottom of the roadbed adjacent to all crossmembers of the layout base (I used open grid, but L-girder would work, too). Next, using C-clamps, elevate the tangent sections to the desired height and fasten the risers to their adjacent crossmembers. The risers on the curved section are, at this point, hanging free beneath the curve. Select the riser on the curve closest to the mid-point of the curve, and using a level (or a grade marker if the curve is on a grade) push the riser straight up until the mid-point of the curve is at the proper elevation. Use a pencil to mark a line across the face of the riser, level with the top of the benchwork crosspiece. The end of this line which is on the inside of the curve is now used as your basic elevation marker - it should always line up with the top of the crossmember during the next step. Now, push on the bottom of this riser towards the outside of the curve, making sure that the inside end of the line always lines up with the top of the crossmember - this will have the effect of raising the outer rail. You can measure this if you want to, but I just placed a few cars on the track and pushed until the curve “looked right”. Fasten this riser in place. All of the intermediate risers between this mid-point and the tangents will now have their bottom ends off-set somewhat from their original vertical position, the offset decreasing as they near the ends of the curve. Simply fasten them in place where they are - it helps to mark their position on the riser or clamp them in place to ensure that you don’t move them while driving the screws. Your