Degree of Banking

[7j43k]

The maximum FRA superelevation is 6".

A typical large superelevation in the US is 3-4".

 

6" (HO) of superelevation can be obtained by shimming the edge of a tie .125".

 

4" (HO) of superelevation can be obtained by shimming the edge of a tie .08".

 

3" (HO) of superelevation can be obtained by shimming the edge of a tie .06".

 

I use .04" shims for my maximum superelevation.  That would be a 2" superelevation.

And a .02" shim will yield a 1" superelevation.

 

Here is the formula I used:

 

(HO tie width/HO gage) x superelevation in prototype inches-----divide by 87.1

this obtains the shim thickness.

 

 

I am VERY happy with my choice of .04" max shims.  It's enough to be visible, but not so much as to be constantly noticeable.   I have 18" transition curves into 48" radius maximum curvature.  The change in superelevation occurs in the transition. Tom described the same thing earlier.

 

Ed

[ROBERT PETRICK]

tstage

On my last HO-layout I superelevated the outside rail of my R22" curves with .020" styrene strips and I made sure the angle to get to that height happened graduallly.  IIRC, it took at least 12" to go from 0 to .020" superelevation and I believe I did it in .005" or .010" incriments.  And, because I increased the height of the outer rail gradually (and started and finished it before the curve), I never had any issues with derailments on those curves.

The superelevation was noticeable but more from ground-level rather than eye-level.  What the final % ended up being I didn't calculate.  If Wayne claimed he had 2.5% superelevation on his layout and he used as much as .050" to achieve that then I'm guessing that my .020" was only 1%.

3% seems a bit steep to me.  For my layout 1% was quite ample.  And, given my modeling goals, I probably wouldn't go higher than 1.5%...but that's me.

Tom

No need to guess. If you put a 0.020" styrene strip under one edge (the very edge) of an HO scale tie, the cross slope would be at least 2% and probably closer to 3% (depending on the width of the shim strip and its proximity to the edge). That is very close to the prototypical maximum.

Robert 

[doctorwayne]

tstage

...If Wayne claimed he had 2.5% superelevation on his layout and he used as much as .050" to achieve that then I'm guessing that my .020" was only 1%.....

Tom, the 2.5% figure is for the grade, not the superelevation.  My original layout was to have grades under 2%, but when I lost layout room space to "other uses", I decided to double-deck part of the layout.  The trackplan is somewhat like the shape of the letter "Y", but with the two upper arms one-over-the-other.  The upper level has no grades, but much of the rest of it is like a roller coaster. 

Wayne

[cuyama]

This thread has drifted. Note that the Original Poster was asking about "banking" (superelevation) to try to mitigate the performance impacts of a grade through a relatively tight curve (having been led down that garden path by a poster on another thread). As I think everyone will agree, superelevation is neutral to negative on performance.

The Original Poster re-designed his layout to avoid the grade through the curve, as he told us on November 23:

starman

From the comments I have received from members of this forum, comments from other railroad molders, and comments from people I know at the train store where I purchase most of my “stuff”, I have decided to redesign my incline and curve so that the curve is NOT part of the incline.

The fellow who refers to himself in the third person resurrected this thread for an unknown reason on Dec. 4, and confusion ensued as subsequent posters replied without checking the earlier posts in the thread.

Cosmetic superelevation on broader curves works fine with enough length given to gradual transitions into- and out of superelevation. But the physics of model trains differ so much from real-life trains that it does not help with performance or reliability.

[tstage]

On my last HO-layout I superelevated the outside rail of my R22" curves with .020" styrene strips and I made sure the angle to get to that height happened graduallly.  IIRC, it took at least 12" to go from 0 to .020" superelevation and I believe I did it in .005" or .010" incriments.  And, because I increased the height of the outer rail gradually (and started and finished it before the curve), I never had any issues with derailments on those curves.

The superelevation was noticeable but more from ground-level rather than eye-level.  What the final % ended up being I didn't calculate.  If Wayne claimed he had 2.5% superelevation on his layout and he used as much as .050" to achieve that then I'm guessing that my .020" was only 1%.

3% seems a bit steep to me.  For my layout 1% was quite ample.  And, given my modeling goals, I probably wouldn't go higher than 1.5%...but that's me.

Tom

[doctorwayne]

cuyama

 doctorwayne

I have not had any problems with stringlining or derailments caused by superelevation on any of these curves

 

 If I remember correctly, your minimum radii are significantly broader than the Original Poster's (22" in HO), aren't they?

 

Yes, most of my mainline curves are 34" radii, and the radius will have some bearing on problems such as stringlining.  However, many of my cars are not what would nowadays be considered "free rolling".  Most roll reasonably well, (and some too well) but I have some real bricks which will not, on their own, roll down a 2.5% grade.   Because these aren't too prevalent, I don't worry too much about their position within the train, but on tighter curves, they could cause problems.
Where rolling qualities are good, I doubt that tight curves would cause problems simply because a layout with tight curves is usually unlikely to have room to run long trains.

 

I am also mindful of train make-up:  if there are cars in the train with "live" loads (usually coal, gravel, or scrap), they are generally blocked near the front of the train, where the excess weight will have no effect on lighter cars which might be in the same train. Light cars, such as empty hoppers, are placed towards the rear of the train, and the longer the train, the farther back they're placed.  
In trains where car weights are fairly consistent, placement within the train isn't an issue.

Superelevation is, on my layout, for appearance only, and trains do look good running on it, especially through S-type curves.  

 

While my superelevation was added "by-eye", I just now measured it in a couple of places, and it varies between .020" and .050", depending on the length of the curve and, of course, the point within the curve.  I'd guess that without a train on it, few observers would even notice it.

 

As for the OP's desire for superelevation, I'd suggest trying it if you can add it easily.  If it's going to be a lot of effort and possibly even more effort to undo it in the event that it proves unsatisfactory, then skip it.  Were I in his shoes, though, I would, of course, give it a try. 

 

Wayne

[jjdamnit]

Hello all,

I noticed that you keep asking the same question in different threads, expecting different advice and/or answers.

As Albert Einstein once said, "Insanity is doing the same thing over and over again and expecting different results."

I am not saying that you are insane but posting over and over again, in different threads, expecting different replies, is not heeding the advice we have graciously given.

Since you are intent on super-elevating your curves I suggest you look up super-elevation.

In the May 2015 edition of Model Railroad Hobbyist magazine; page 33, there is a Q&A regarding superelevation.

The recommendation from MRH is that it should not exceed 1/16-inch (1.5 mm) for HO scale.

On my flat curves I use 1/32-inch (0.75 mm) thick wood coffee beverage stirrers on the outer edges.

Some will question my use of wood over styrene, fearing swelling of the wood during ballasting. 

I adopted the ballasting method mentioned in a previous thread http://cs.trains.com/mrr/f/88/t/258968.aspx and have no swelling of the wooden stir stick used for superelevation.

Hope this helps.

Insanity: doing the same thing over and over again and expecting different results.
Read more at: https://www.brainyquote.com/quotes/quotes/a/alberteins133991.html

Insanity: doing the same thing over and over again and expecting different results.
Read more at: https://www.brainyquote.com/quotes/quotes/a/alberteins133991.html

Insanity: doing the same thing over and over again and expecting different results.
Read more at: https://www.brainyquote.com/quotes/quotes/a/alberteins133991.html

[cuyama]

doctorwayne

I have not had any problems with stringlining or derailments caused by superelevation on any of these curves

If I remember correctly, your minimum radii are significantly broader than the Original Poster's (22" in HO), aren't they?

[jwar41]

The rails, tie plates and ties are the same as on flat track. On elevated track the tie is elevated on one side,  giveing what is called the super on 1:1 track. Wheel trreads (cars and Locomotives) have a one in twenty taper across the whell tread, this works somewhat like a differental in a car, to elavate one track above the tie plate, would cause excessice track ball wear and tread ware

[doctorwayne]

I superelevated all of my mainline curves, most of which are on grades of up to 2.5%.  
I don't know the degree of superelevation, since I simply placed a train on each curve (the track was already in place on the cork atop 3/4" plywood subroadbed), and, using the procedure outlined below, imparted superelevation until it looked good to me.

I have not had any problems with stringlining or derailments caused by superelevation on any of these curves - my operations are all DC, and I use helpers and/or pushers on most trains.  Train lengths are usually under 20 cars, but I have run trains in excess of 70 cars and of trailing weights in excess of 20lbs.

This is my method of adding superelevation:

If you use open grid or L-girder benchwork, superelevation is easy to add, including the vertical easements into and out of the curve.

I use 3/4" plywood as a sub-roadbed, but any similar-type material, or even spline roadbed should also work.  Install the straight roadbed on either side of the curve by fastening the risers to the joists, except for the last riser beyond the ends of the curve.  Install risers to the underside of the curved roadbed, but don't fasten them to the benchwork just yet.  If your curve is on a grade, as most of mine are, raise the roadbed through the curve to the proper height, then mark a pencil line on each riser which corresponds to the top of the benchwork to which it will eventually be fastened.  If the track through the curve is to be level, adjust the risers accordingly, then make the lines.  Next, choose the riser closest to the mid-point of the curve, raise it to the proper height, then push the bottom end of the riser towards the outside of the curve.  Re-align the height line on the riser so that its inner end corresponds to the top of its benchwork member (the height line will be tilted, with the end on the outside of the curve somewhat above the benchwork).  I've found that the best way to establish the amount of superelevation is by placing a train on the curve, then adjusting the off-set of the bottom of the riser until it "looks right".  I use a C-clamp while I'm making the visual adjustments, then, when I'm satisfied with the appearance, that mid-point riser is screwed to the benchwork.  Because the roadbed is torsionally flexible, each riser on either side of the mid-point will now be off-set from the vertical, to diminishing degrees, as the distance from the mid-point increases.  Working from the mid-point of the curve, carefully raise each riser so that the inside end of the height mark aligns with the top of the benchwork to which it will be fastened, making sure to not change the angle of off-set, then screw the risers to the benchwork.  This allows the roadbed to form its own easements into and out of the super elevation.  I did all of mine with the trackwork in place.

Wayne

 

[selector]

BroadwayLion

When rails are banked (1:1) both rails remain perfectly vertical. The space is put between the tie plate and the tie. The tie remains level...

 

 

 

ROAR

 

Not true, or not necessarily so, Brother Lion.  They can't be level because the rails have to have their own cant relative to the geometry of the tire faces rolling over them.  Since wheel rims on trains are truncated conical sections, the bearing surfaces have to match.  As John Armstrong noted in a widely disseminated diagram, the rail webs are inwardly canted to provide a good match for the conical surfaces of the wheel tires.  That match would be ruined if one rail were elevated and both were kept strictly vertical.

The ties in this image are clearly not level across their repose.

 

[BroadwayLion]

When rails are banked (1:1) both rails remain perfectly vertical. The space is put between the tie plate and the tie. The tie remains level.

On model railroads we typically cant the entire piece of track, so that the ties are no longer level. This in the 1:1 world would apply forces inproperly causing rail fractures. This is of little consquence on 1;87.

LION banked the sub-road bed of his helix. The ties are flat to the sub-bed and thus the geometry of the system is improved. The helix of LION is a four track mane line: The risers have flat tops, but then builder's shims are used between the riser and the bottom of the track deck. Obviuosly this cant continues to the next level since little risers are used between the levels.

LION has had no problem with this project. YOUR WORLD may vary.

 

ROAR

[starman]

From the comments I have received from members of this forum, comments from other railroad molders, and comments from people I know at the train store where I purchase most of my “stuff”, I have decided to redesign my incline and curve so that the curve is NOT part of the incline.  I will have enough room, with some redesigned, to have about a 20” flat section of track before going into the curve.  I am going to mock up this new design and see how it works.  Thank you all for the comments I have received.  I knew I could count on members of this forum!

[cuyama]

starman

Many people have recommended I bank my HO 22” radius curve that is on a 3% incline.

Folks on this forum suggested that you should not superelevate ("bank") your curves in your other thread.
http://cs.trains.com/mrr/f/11/t/259546.aspx

At best, it won't improve performance - at worst, it may make trains more likely to derail across the center of the curve. Just as was explained in your earlier thread.

[dknelson]

If by banking you mean "super-elevation," that serves a real purpose and need on the prototype, but on our models it is almost, and perhaps literally, entirely cosmetic.  And banking a curve on a flat surface is one thing; but on an incline has its own issues.  If it is to be banked at all, I would say only enough to be noticable (that does not take much, just a thin shim or two on the outside rail of the curve).  And I would say, dummy up an example with old track and test it before you commit.

I super elevated the curves on my (flat) layout.  Things do look neat leaning into the curve.  But when I decided I needed to install a turnout on  a particular curve, I reluctantly ripped the super elevation out.  I could foresee the disasters.

Dave Nelson

[starman]

Many people have recommended I bank my HO 22” radius curve that is on a 3% incline.  If I do this, what degree of banking would you recommend?  Thanks.