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Super Elevation and grades

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  • Member since
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  • From: Brampton, Ontario, Canada
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Super Elevation and grades
Posted by V&A C-628 on Sunday, July 11, 2010 8:29 PM

I've read many articles on how to super elevate curves. Can someone please tell me which issues of MR mention how to super elevate curves? Also, I've been trying to figure out how to calculate gradeint regarding how high the tracks should climb on  1.0%, 1.5% and 2.0% grades? Is there a good height at which to end such grades?

My screen I.D will include a photo once I have found and painted a high hood C-630 in my railways 1960's scheme. I thought I had the paint scheme firgured out, but I'm still deciding and trying new ideas. I plan on making a website for my railway some time soon. Once it's up, I'll give the web address.

Prototype-base freelancing West Virginian Ry. with Virginian Ry. as base prototype. Modeling the fall of 1973 in western Virginia, eastern Kentucky, and southern West Virginia. Electrified helper district over the Blue Ridge Mountains with EL-C's and a few other electrics.

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Posted by cowman on Sunday, July 11, 2010 9:24 PM

Sorry I can't remember which issue or special issue superelevation was in.  I'm sure if you check Resources at the top of the page than go to Index of Magazines, you can find several references.  Also, check the search option to the right.  I've had a rough day or I'd look it up for you.

A grade is to get you up to a new height.  There is no limit (except for space) on how long a grade can be, so it can if you go a foot, it will only raise a little, if you go 100' it will raise you a lot more, regardless of the % grade.  What does matter is if you plan to raise your track enough to have have clearance to cross over itself.  Then you have to calculate how many feet you have to achieve the needed clearance and then calculate the grade.  ie, if you have 8' (96") to go up 4" you have about a 4% grade.  (Would be exactly 4% if you had 100" to make the 4" rise in.).  The steepness of your grade will determine how many cars a given loco or combination of locos can pull up it.

Hope this helps.

Have fun,

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Posted by selector on Sunday, July 11, 2010 11:06 PM

V&A1533
...Is there a good height at which to end such grades?...

 

Please don't think me a churl, but your question suggests to me that you aren't really up to speed on the need for grades in the first place, at least not as they fit into a track plan for your layout.

How tall is a person?  The question in not really answerable, and for grades as well.  It depends on where you need the trains to be in elevation, but also what elevation you started at in the first place.  Why have a grade if you don't need one, or if you have no real purpose?  Do you need a grade to an industry, say a logging camp or a mine?  Where is it to be, and how much higher than the place where your grade will start at the lower level?  How far of a 'run' do you have to get to this new elevation?  The run and the height determine the grade, and a steep grade becomes steep work for a locomotive.

A long way to say that you should consider a track plan with operational/revenue generation and if you wish to have a grade, what is a reasonable one for the engine you intend to work it?  Maybe a 3% grade will work, but maybe even a 2% grade won't work.  So, you must answer the question based on what you would like to do.  If you find it is not going to work, revise your thinking and plan.

As a guideline, 3% grades are about all that look and work well in the model world, although steeper ones can be made to work, particularly if you are willing to use two engines as they do in the real world.  Most of us try to limit grades to under 2.3%, and so do the real railroads.

-Crandell

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Posted by BATMAN on Sunday, July 11, 2010 11:51 PM

 If you look at this photo you can see the climb the train will make. Look at the centre at the far end of the room. This is about 6 inches above the bench. I needed it to be that high, in that spot, for a reason. I could have done the climb in less space and maintained a 2% grade along the whole length of the climb but instead chose to make the climb longer and more gentle. From where the climb starts to where it reaches the height I wanted, the grade varies along the way just as it does in the real world when a train grinds up into the Rocky mountains. It never exceeds 2% though. The thing to remember is, the steeper the grade the shorter the train or the more engines required. If you want a hill just because you want a hill that's fine. But if it serves a purpose work out what you need and what you can get away with. I hope this helps.Smile

I wouldn't  worry about super elevation until you have everything else figured out. Just myMy 2 cents

 

                                                                          Brent

Brent


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Posted by ChevelleSSguy on Monday, July 12, 2010 12:24 AM

The October 2008 MR has an article on page 44 and 45 for doing superelevation.

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Posted by norcalmodeler on Wednesday, July 14, 2010 5:25 PM

i have a question, how long is your room? 

from what i am reading you have less than a 2% grade and you reach 6 inches by the time you get to the back of the room by the window under the window.

so by my calculations to reach 6 inches a

2% grade is 25 feet of track

1-1/2% grade is 33.33 feet of track

1% grade is 50 feet

i guess why i am asking is it does not seem to be that far.

am i missing something

i use a 48" level with a 1 inch block under it or a 24" with a 1/2" block under it keeps me around a 2-2.25% grade

just checking, 

 

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Posted by tomikawaTT on Wednesday, July 14, 2010 5:57 PM

Curve superelevation has been covered many times on these forums, but here's a condensed version of what has been posted before:

  1. Superelevation of models is purely cosmetic.  It isn't needed unless you operate your trains at speeds measured in Mach numbers.
  2. A little superelevation, say 1mm across a 16.5mm gauge track, is plenty - and plenty prototypical.  IIRC, BNSF new construction in Abo Canyon specifies 3.5mm Oops inch (my bad!) superelevation on track to be run at moderate speed.
  3. There are about as many ways to superelevate model curves as there are modelers who build them.  To name a few, from least to most drastic: masking tape, cardstock or balsa under the outer ends of the ties, wedges or strips of ??? under the ballast former (cork or foam roadbed), tipping the whole cookie-cut structure by manipulating the risers (only possible for cookie cut subgrade on risers over grid or L-girder structure.)  Folks who build on splines can slope the spline structure from one side to the other, or tip it.
  4. For most prototypical results, superelevation is best accomplished in conjunction with spiral easements - zero superelevation at the tangent end of the easement, gradually increasing as the radius of the spiral decreases, finally reaching full height where the true curve begins.  That's the way our full-scale friends do it.

 

To 'calculate' gradient, measure units of rise for 100 units of run.  As for a good height to end a grade, the short answer is, "At the height you have to reach."  That might be just high enough to go up and over another track, or the top of (prototype) Soldier Summit, Donner Summit, Usui Pass or Pike's Peak.

To reach the top of Usui Pass, the best the locating engineers could arrange was a 6.8% grade.  That line has since been abandoned - bypassed by a Shinkansen route!  You can still get to the top of Pike's Peak by cog railway - if you make reservations well in advance.

Chuck (Modeling Central Japan in September, 1964)

 

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Posted by twhite on Wednesday, July 14, 2010 7:10 PM

My feeling is that on a model railroad grade, super-elevation is something that is really not needed, especially if the grade is steep and the curves are tight.  All that does is increase the possibility of 'stringling' a fairly long train around the curve. 

My HO Yuba River Sub has grades between 2-2.4%, but it also has relatively generous curves of between 34" and 36" radii on those curves.  It's also a fairly large (24x24') garage layout, so there's nothing 'tight' about either grades or radii on the whole.  I can run 25-40 car grains up the grades without worrying about 'stringling', and none of the curves are super-elevated.  

Super-elevation to me denotes fast running on relatively level track.  There's only one portion of my layout that could possibly fit that description (a hidden large reverse curve) and even then, the maximum speed I allow is about 50 smph.  The rest of the layout--mountainous--is restricted to between 25 and 40 smph, which to my thinking, hardly requires super-elevation on curves. 

Just my thoughts.

Tom Smile  

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Posted by BATMAN on Wednesday, July 14, 2010 9:01 PM

norcalmodeler

i have a question, how long is your room? 

 

Whoops! I lied. It is only 5" high mid window. Sorry about that. It was done a while ago. Old brain cells don't ya know. Whistling

  The room is 24' long. The grade starts just before it does the 180 degree turn in the foreground. The total length of the climb ( I had to go count flex track pieces Laugh ) is about 35'. So 5" over 35'. Not a tough climb, but it does have some 2% parts

I have also built in super elevation into my splines. It was quite easy to do with a rasp if you're patient.

 

                                                                             Brent

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Posted by wjstix on Thursday, July 15, 2010 8:22 AM

Super-elevation on curves does actually slightly reduce the effective radius of the curve, so it's not purely cosmetic - although the greatly increased realism in the appearance of track that's superelevated is the primary reason for using it in models. You can do it many different ways: If you use roadbed made of cork or upsom board (like "Ribbonrail" in the Walthers catalogue) you can raise the outside of the roadbed and then lay track on top of it, or you can keep the roadbed flat and raise the outsides of the rails. If you use Woodland Scenics risers, you can raise the outside edge of the risers. In any case, you can as noted use layers of masking tape, or pieces of dimensional scale lumber (either wood or plastic).

Stix
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Posted by norcalmodeler on Thursday, July 15, 2010 10:27 AM

 thanks,

i was just making sure i was doing it right.

i have a 3 level layout and all levels are connected by a 2% to 2.5% grade.

i run a double track with 32 radius inside and 34.5 radius outside track.

i will have to run large steam or double headed diesels to get up the grades i have created.

which is fine for the area i am modeling

 

BATMAN

norcalmodeler

i have a question, how long is your room? 

 

Whoops! I lied. It is only 5" high mid window. Sorry about that. It was done a while ago. Old brain cells don't ya know. Whistling

  The room is 24' long. The grade starts just before it does the 180 degree turn in the foreground. The total length of the climb ( I had to go count flex track pieces Laugh ) is about 35'. So 5" over 35'. Not a tough climb, but it does have some 2% parts

I have also built in super elevation into my splines. It was quite easy to do with a rasp if you're patient.

 

                                                                             Brent


 

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Posted by Medina1128 on Thursday, July 15, 2010 12:34 PM

tomikawaTT

Curve superelevation has been covered many times on these forums, but here's a condesed version of what has been posted before: There are about as many ways to superelevate model curves as there are modelers who build them. 

To name a few, from least to most drastic: masking tape, cardstock or balsa under the outer ends of the ties, wedges or strips of ??? under the ballast former (cork or foam roadbed), tipping the whole cookie-cut structure by manipulating the risers (only possible for cookie cut subgrade on risers over grid or L-girder structure.)  Folks who build on splines can slope the spline structure from one side to the other, or tip it.

     Chuck (Modeling Central Japan in September, 1964)

     

     

    I use strips cut from a "For Sale" sign that I bought at Wal-Mart. I have styrene templates that go all the way up to 29" radius. I trace out the curve that I need, then cut them out with scissors. I apply them with acrylic caulk. After it's set up, I use caulk to install the track. I use pushpins to hold the track in place until the caulk sets up.

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