Prototype Information
Engineering
The WWSL
It's A Visual Thing Only
On my previous HO layout to this one, I went to a LOT of trouble to super-elevate all the mainline curves. It was a royal PITA to do so. However, on some of the curves (curves viewed from the outside of the curve) where it could be seen, it was worth it. The others (viewed from the inside of the curve)... a waste.
On my current layout, there's only one curve on my layout that would readily show super-elevation: The upper level turn back curve (viewed from the outside of the curve) on the end of the peninsula that slaps you in the face near eye level upon entering the room, or when walking around the end of the dual level peninsula blob.
I also only have one curve viewable from the outside on a central peninsula. All the other curves are around the walls so basically you are inside the curves. I also have most of my curves within a city and industrial/harbour areas and one curve goes into a tunnel and over a bridge so a large part is hidden no point doing superelevation there.
i like the thought that it’s worthwhile only if you see it.
Modeling Information
There are three ways to model superelevation for curves.
First. Tape .
I got the masking tape approach from an article by Paul Dolkos many years ago.
the tape thickness is around .003 inches, not .02 as I said earlier. I use 6 layers, giving me about 1.57 scale inches of rise on the outside rail. xxxxx layers under the outer rail equates to about 8 1/2 inches in HO, which looks very good. Even my Challenger and other large articulated steamers have no problem negotiating the ramps into and out of the curves.
Adding it is easy...I use 1/4” masking tape, placed under the outer edge of the track (flex track). Build up layers — start the first at the beginning of your easement (ending at the other end of your easement) then start each successive layer about 2” later into the curve.Second. Stripwood / styrene
I opted for the styrene method so I had more modeling material when I was done doing the super el. I used styrene strip material, .010"--.020"--.030" X .100" wide. I cut the strips into lengths to span 3 or 4 ties. Starting at the center of the curve with the thickest strip, I then filled in each side of the gap with the other strips to fit. Don't need to put strips end to end, I spaced the strips 2-3 ties apart. Figured ballast would fill the gaps. You did spiral easments, hardly anymore trouble to do super el. Tony's pic above says it all.....nice!
I decided to glue down styrene strips 1.75" long. The first strip was .005, then .010, 015 up to .055 thick at the middle of the curve. This is working well.
Then I glued the track down with Dap Clear Kwik Seal caulk. I weighed down the track with food cans from the pantry until the caulk dried.
Third - Cant the subroadbed. Paul, I used
MDF splined roadbed on that now-defunct layout. To get the
super-elevation, I merely canted the risers supporting the roadbed
splines. Instead of having them plum, I'd tilt the top maybe a degree and a half, perhaps more, and when the splines were attached they adopted the correct super-elevation. From there, I affixed the ties directly to the roadbed using a thin sheen of DAP acrylic latex caulking.
Jul 04, 2020
Do it
If the type of railroad you are modeling has superelevated curves then do it. It is pretty easy to do and should not impact operations at all.
I just glue down strips of low profile ties on one side of the track location and then why dry sand down the ties leading into and out of the curve to make a smooth transition. I then glue down the track on the curves the same as any other section using DAP silicone. Track has been in place for at least ten years without any problems and my long trains have no problem going around the 30" minimum radius curves. It is somewhat subtle but the combination of easements and super elevation really makes everything look right.
Third. Wire
I am going to use the first technique: tape.
Project Process
1. Layout the curve
2. Layout the superelevation
3. Lay the track.
During the building of the curve templates, I had marked, on the templates, the transitions from the tangent (straight) to the spiral, the spiral to the arc of the curve, and then at about every 11 degrees through the curve(45 /2 ~= 22, 22 / 2 = 11). These markings were transferred to the roadbed when the templates were used.
I used thin (1/4" wide) strips of masking tape under the location of the outside rail on the roadbed to elevate the rail. The first layer starts on the tangent about a foot before the beginning of the transition spiral to hike the train up before it enters the curve. The strips of tape go all the way to the corresponding location on the other end of the curve. Another layer (or layers) goes from the beginning of the transition spiral through the curve. The last layer(s) go from the beginning of the arc of the curve to the end of the arc of the curve. We had fairly thin masking tape, so we used 2 layers, 2 more layers, and then 3 more layers (total number of strips = 7) for ours. Thicker masking tape might require something less. The effect is subtle but noticeable.
Once the track is down, ballast as you normally would. You can cut the strips on a sheet of glass with a razor knife and metal-edged ruler.
Reference
Mark Couvillion, Laying Out Easements with Transition Spiral Templates in HO, The Derail — October 2017
| Cant Height (in) | Cant Height HO (mm) | Cant Height (in) |
| 0.5 | 0.146 | 0.006 |
| 1 | 0.292 | 0.011 |
| 1.5 | 0.437 | 0.017 |
| 2 | 0.583 | 0.023 |
| 2.5 | 0.729 | 0.029 |
| 3 | 0.875 | 0.034 |
| 3.5 | 1.021 | 0.040 |
| 4 | 1.166 | 0.046 |
| 4.5 | 1.312 | 0.052 |
| 5 | 1.458 | 0.057 |
| 5.5 | 1.604 | 0.063 |
| 6 | 1.750 | 0.069 |
Generally, less is more. Some overdo super-elevation and it looks ridiculous. So, with that small increment you mentioned, you are on the right track.
Super-elevation has two main considerations: speed and curvature.
You don't need to spackle to fill voids. Ballast grains, once groomed to look right, will do that, and the glue will do the rest. Save yourself the trouble.
Super elevation should not exceed 6 Prototypical inches. 1/16 inch for HO, 1/32 for N scale
3. Even with a slight elevation, you want to ease into your maximum height. So in other words, you would not want to go from no elevation to your maximum elevation in one step.
Also, "don't force it"! A tighter curve radius may prevent going with the maximum allowable elevation. Don't try and increase your elevation to rapidly to "make it fit"
Reference.
Michael Highsmith Superelevation Made Easy
superelevation in a helix
I should mention here that on my helices I super-elevate the curves in reverse to avoid a train string lining on the grade. I use 1/16" styrene under the inside edge of the ties, which makes for quite a bit of reverse super elevation. Though the outside rail in this case is unsupported as you say, I've never experienced any problems yet.
I used 1/16" X 1/8" stripwood; the 1/16" side for the elevation. I also sanded "ramps" at the ends of the stripwood to form a gradual easement into the
I place 1/4" masking tape (try an art supply store if your hardware store doesn't carry it) on top of my Homabed subroadbed, at the edge, building up every 2" to 12 total layers. That's right, a 24" total transition, longer than my actual curve easements. I found 1" looks too abrupt, almost like a "ripple" when you sight down the rails. I use adhesive caulk to secure my track, which also permanently secures the tape.
Very easy to do and looks fantastic. The track is smooth and well-supported even without ballast. On a large turnback curve, I used thin plastic weedwhacker line secured with adhesive caulk for the bulk of the curve. This was tricky and required a bunch of pushpins to secure it while it dried, so I'd use styrene or stripwood next time, again with the masking tape transitions.
p.s. the tape likes to begin curling up if you leave it too long, as it doesn't stick terribly well to homasote. I apply it the same evening I plan to lay the track, then the caulk holds everything together as mentioned. Or if you run out of time, apply a small flat weight to each end.
As Billso described, I also use masking tape to create super elevated curves. But I only use 8 layers. I have found standard masking tape at the big box stores averages between 3.5mil to 5mil. At 8 layers this is close to 1/32 inch as mentioned by many of the other posts.
I also buy or cut strips from wider rolls, 1/4 inch tape. I start with a single layer on the outside radius for the entire length of the curve I want super elevated. I then place a second layer, moving in 2 1/2 inches from both ends, for that entire distance. Move in another 2 1/2 inches and place the third strip.. etc. etc.
My minimum radius for my double track main line is a 30 inch radius, this makes the length of a 90 degree curve 47 inches. By placing each layer 2 1/2 inches from the ends and using 8 layers max, I have a nice easement with a foot of constant, approx 1/32 inch super elevation in the middle of the curve.
It is perfect in HO. We have learned one thing that is not in the article, under no circumstances pull the tape taught as you lay it. Instead, just give yourself enough lead to gently press it down in place. If you pull it taught, it will recoil on you. Once it pulls up, you're probably going to have to take it out and start over.
Another update to the technique, the method calls for masking under the roadbed. We have found that you can simply do it under the track. I prefer the roadbed way, but if you find a curve that you would like to SE, just pull up the track and go for it.
With the under track method, get the track back down quickly, but do not over drive the track spike, just get it in there snug. We also recommend ballasting sooner than later. The glue forms a rock solid foundation and assures the tape will not pull up.
Finally, in a recent application, I ran the first layer of tape a little long and used a push pin to hold it down. Once done, I just trimmed it to the length I wanted. We were having a humidity issue and I could not get the tape to stay (tape on bare homabed). This solved that. Thanks again, Michael
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