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Super Elevation

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Super Elevation
Posted by Track fiddler on Monday, August 14, 2017 5:25 PM

Things that make you go hmm.  

It seems to me the concept of super elevation is a no-brainer for its designed purpose of higher speeds it only makes sense the slant works positively with the centrifical force.

But what about pulling a long string of cars around a superelevated curve at a very slow speed.  It's my thoughts the extra drag weight of a long train on a curve at a slow speed already has a string line force pulling the cars towards the middle of the radius.  Then you factor into the equation the super elevation slant and gravity. It seems to me there would be an extra added downward Force on the wheel flange riding the inside rail.  

Therefore at a slow speed would superelevation actually be a negative adding more friction than just a level track.

Not that anybody or I would even think about doing it.  But it almost seems to me at a slow speed the curve leaning out would be more of a positive aid to the physics.

Your thoughts? 

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Posted by 7j43k on Monday, August 14, 2017 5:34 PM

On prototype trains, there's a "design speed" through superelevated curves.  And, yes, there are inefficiencies when going slower.  And also faster.  So the designers consider the whole range of trains likely to go around the curve and (hopefully) pick the best amount of superelevation.  Among the options is zero superelevation.  Which is what is chosen for curves on industrial trackage.  Usually.

 

Ed

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Posted by BigDaddy on Monday, August 14, 2017 5:39 PM

Take the tour of Daytona Racetrack.  Slow speed would be bad.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by Track fiddler on Monday, August 14, 2017 6:02 PM

Interesting Ed.   What you just said makes perfect sense.  

The reason I brought this up is I am considering super elevation.  I no longer want to see how fast my trains can go like when I was a kid but smooth and reliable trains running at faster speeds in moderation would  be nice to be able to do without problems.   It is also nice to run your trains real slow sometimes too.  I guess it depends on what kind of mood you're in.  

There must be some kind of safe happy medium for choosing an effective but not overboard super elevation for both faster and slower speeds.  

Just dipping into beginning research here.  I have speculatory thoughts but nothing concrete enough to move ahead.

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Posted by cuyama on Monday, August 14, 2017 6:14 PM

The physics are different, model and real thing. Superelevation is cosmetic only on a model railroad. It does not improve performance, and may actually slightly increase the risk of stringlining and derailing to the inside on very tight curves.

Many threads on the forum, same conclusions. Here's one

http://cs.trains.com/mrr/f/11/t/259681.aspx

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Posted by 7j43k on Monday, August 14, 2017 6:45 PM

Track fiddler
 

There must be some kind of safe happy medium for choosing an effective but not overboard super elevation for both faster and slower speeds.  

 

There is, but I think it's much more for aesthetics than operation.

I use .040" thick shims out at the end of my ties.  There is an 18" long transition section from straight to a 48" radius curve.  There is also a transition of shim thickness in that distance.  Track is Code 83 Walthers.

I've never had a derailment on those curves.

And the track really looks nice with the superelevation.  THAT is why I do it, not for improved performance.

 

Notice, by the way, that I'm not running those tight curves Cuyama is talking about. But then, who superelevates industrial trackage, anyway?

 

Ed

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Posted by Track fiddler on Monday, August 14, 2017 7:16 PM

Thanks for the link cuyama.  I do remember reading that thread.  I just didn't remember it was less than a year ago.  

It's tough and almost impossible to come up with a new subject that hasn't been discussed before.  I guess the trick is to come up with a subject that hasn't been discussed too recently.  That thread wasn't as much interest to me at the time as it is now.  I wasn't to that point on my build to consider it.

I have a super small detail sander that I could easily sand my cork to do slight super elevation but maybe I should just keep leave well enough alone.  

I spent the extra time to make sure the side to side of my cork is very level.

If any other members on the Forum have things good to say about super elevation and are happy with thier results I may still consider it. 

I think the cosmetics of super elevation would be way more noticeable on HO scale to be a more worthwhile effort than it would on N scale. 

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Posted by Track fiddler on Monday, August 14, 2017 7:52 PM

Okay now we're getting somewhere Ed.  I like shims what carpenter doesn't like shims.  But we got some apples and oranges going on here.  A grade is a grade it's all the same from Z scale to a prototypical Railroad.  But I would have to divide your shim by 1.839 the width difference from HO scale track to N scale track is (N160/HO87) whatever that comes out to.  

I as well do not have tight radiuses. My minimum viewable radius is 18" equivalent to 33 in HO.

Do you think the Cosmetics of superelevation will be worthwhile in N scale.

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Posted by 7j43k on Monday, August 14, 2017 8:06 PM

N, huh?

Well, interesting.

For N you'd just use half as thick as HO.  .020"

And 33" equivalent sounds promising.  

Don't ferget, you're goning to have to ease and taper things.  Which you may not have done with your just installed cork.  Well, maybe you can skip the easement.  Better not to, but if the cork's in place, you just did.

 

But whether it will work in N?  I surely don't know.  Perhaps you will be the leader on the matter.  Unless an N person pipes up.

I can suggest that, since it looks like you've got your cork down waiting for track, try a 'spearmint:  lay a piece of track all by itself onto a curve.  Don't bother with wiring or any other track.  Put those .020 shims in while you do it.  Then peer at it.  Does it look worth it?  To really see the effect, it's best to be down at the end at track level.  Cool?  Or not really?  If you go for it, you don't have to necessarily be in that position again to see it.  It's kind noticeable all the time.  Except you don't notice it.  If ya get me.

 

Ed

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Posted by Track fiddler on Monday, August 14, 2017 9:52 PM

7j43k

Don't ferget, you're goning to have to ease and taper things.  Which you may not have done with your just installed cork.  Well, maybe you can skip the easement.  Better not to, but if the cork's in place, you just did.

If ya get me.

 

Ed

 

Ed.   You mean like this. (See below image)  Yeah I getcha sweetheart.

Feeling a little cocky tonight.  I like that.  I'm a little cocky too.  My dad was extremely cocky.  A retired marine sergeant and was very well liked.  He had loads of friends. You should have seen his funeral, it was like a darn parade.  Cocky is hard to read on black and white text.  You can't see the facial expressions.  Cocky is only good when you can see the facial expressions of the person's personality.  

Then it's funny and everybody likes you.  I can see your facial expressions in your text because I'm cocky just like my dad.

Oh you mean like this here's my easements that I did do cutting my foam and laying my cork

Thanks for helping

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Posted by cuyama on Monday, August 14, 2017 10:15 PM

I don't remember the exact heights, but yes, folks have done superelevation in N scale. It's certainly visible if your eyes are near track level. Easing into and out of the full amount of superelevation will be important.

Google: Superelevation "N scale"

You'll find quite a lot.

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Posted by doctorwayne on Monday, August 14, 2017 10:21 PM

My reply regarding superelevation is in that linked thread, too, and it includes an easy way to add superelevation if your layout uses cookie-cutter plywood sub-roadbed.
It is, however, strictly for appearance, as  none of my trains travel fast enough to require it on curves.  The highest allowable speed is 40mph uphill on the longest (45') grade.  Most trains can't sustain that for more than the couple hundred feet to the first of many curves.  The downhill limit on the same grade is 20mph, and a train of any considerable length makes it difficult to hold it below that.  The superelevation causes no particular difficulties despite the slow speeds, but the trains do look good leaning into and out of the many curves.

Wayne

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Posted by dknelson on Tuesday, August 15, 2017 5:55 PM

My home town was on the Chicago & North Western's "old" line between Chicago and Milwaukee, and in the days of the "400" the passenger trains really flew through town, probably close to 90, including a major curve at a grade crossing.  There were some freight trains but most freights were routed over the parallel "new" line a few miles west.  When the passenger trains slowed down and then were removed due to Amtrak, the CNW adjusted the track to remove most and perhaps nearly all of the super elevation.

Since I do model the passenger train era I included super elevation at key curves using PSC's super elevated flex track (plastic nubs on the ends of the ties).  I believe Kato makes super elevated Uni Track in N scale that MR used for a project railroad some years ago.  It looked good. 

Dave Nelson

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Posted by PRR8259 on Tuesday, August 15, 2017 6:57 PM

Given the choice between wider model railroad curve radius and superelevation, it is more important to provide a wider radius wherever possible.  Also superelevation does lead to stringlining especially if overdone in the model world.

I have no superelevation to speak of on my current layout at all, but there are 28.75" "easements" into the tightest mainline curves, which are 26.375" radius (English equivalent of a metric dimension).  Some of my mainline curves are 30" and 32" radius.   My trackwork is not perfect: some joints are a little bit rough, but it is good enough that I can take any currently available engine (I've tried many) and run them flat out as fast as they can possibly go in DC or in DCC, and they will stay on the track.  Challengers and 2-8-8-4's are no problem at all.  Mainline turnouts are the Peco wide radius curved turnouts.

Big 4-8-4's are more of a challenge, but usually work, as well.

John

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Posted by Track fiddler on Sunday, August 20, 2017 12:27 PM

John, Dave, Wayne, Ed, and Cuyama.  Thanks all for the replies.  

All your knowledge on the subject was very informative.

Being that it appears you all agree that superelevation is for Cosmetics only and not function and that almost all my layout is a 2% grade except for the Industrial areas, I know radius adds resistance to the grade as well.  

So after all your information I think I'm leaning towards not doing superelevation and just leaving well enough alone.

Thanks all.  Have a a great day !

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Posted by jjdamnit on Monday, August 21, 2017 1:12 PM

Hello all,

Check out this previous thread...

http://cs.trains.com/mrr/f/13/t/247100.aspx

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

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Posted by ndbprr on Monday, August 21, 2017 5:16 PM

Many years ago I used to ride the Reading RDCs from Fox Chase into Reading Terminal in Philadelphia.  The Olney station was on a sharp superelevated right hand curve on which the train would stop.  You soon learned that preferred seating was on the right side of the train because you would slide off your seat on the left side.  When the train started up the trucks would climb up the top rail and slide back down to the inner rail several times before the track leveled out again.

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Posted by Alantrains on Monday, August 21, 2017 5:45 PM

Kato makes superelevated unitrack for their N scale Japanese Shinkansen bullet trains. It includes transition pieces that go from flat to canted which should prevent any problems. I hope to get some to run some high speed trains on my Japanese layout.

Alan Jones in Sunny Queensland (Oz)

 

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Posted by Track fiddler on Monday, August 21, 2017 8:12 PM

ndbprr

Many years ago I used to ride the Reading RDCs from Fox Chase into Reading Terminal in Philadelphia.  The Olney station was on a sharp superelevated right hand curve on which the train would stop.  You soon learned that preferred seating was on the right side of the train because you would slide off your seat on the left side.  When the train started up the trucks would climb up the top rail and slide back down to the inner rail several times before the track leveled out again.

 

You soon learned to sit on the right.  I bet you did. chuckle chuckle.  Your short story made me laugh. Thanks for the humor.  I needed that.

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Posted by selector on Monday, August 21, 2017 8:23 PM

As people have said, it's strictly for looks, but that makes it kind of important.  It helps with the 'realism'.  In fact, many of us end up taking photos and publishing them on forums and even entering informal and formal competitions.  In that case, your tracks had best look the part.  It's like weathering rolling stock; you needn't do it, but if you'd like a strong gee-whiz factor, especially in images you offer for public viewing, it is almost a must.

 

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Posted by NittanyLion on Monday, August 21, 2017 8:51 PM

ndbprr

Many years ago I used to ride the Reading RDCs from Fox Chase into Reading Terminal in Philadelphia.  The Olney station was on a sharp superelevated right hand curve on which the train would stop.  You soon learned that preferred seating was on the right side of the train because you would slide off your seat on the left side.  When the train started up the trucks would climb up the top rail and slide back down to the inner rail several times before the track leveled out again.

 

Harpers Ferry is the same.  Those Superliners feel like they're tilted over quite periliously when you're sitting at the station.

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Posted by Track fiddler on Monday, August 21, 2017 9:10 PM

Alantrains

Kato makes superelevated unitrack for their N scale Japanese Shinkansen bullet trains. It includes transition pieces that go from flat to canted which should prevent any problems. I hope to get some to run some high speed trains on my Japanese layout.

 

Oz.   That sounds cool.   I bet you have more availability over there where Kato is manufactured.  

I've never seen anything like that at my hobby store as I'm not a big internet shopper.

For real if your modeling bullet trains I would bet superelevation is not only a serious consideration but a must.  So I kind of gather your figuring a way to make it work and make it functional.

Interesting stuff.   Update how that works for you and thanks for your reply.

 

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Posted by Track fiddler on Monday, August 21, 2017 10:03 PM

Selector.   I can really appreciate what you had to say but I am not looking for any magazine entry, or a gee-whiz factor.

I am just after smooth operation and trains not falling off the tracks.

Even with 2% grades and 18 inch radius N scale (very mild).  I am hesitant about adding a third variable of super elevation now.

If it had added function. Definitely yes.

Strictly cosmetics and another negative aspect, not so much.  

Just better off to leave well enough alone.

Do you think ?  I do respect your opinion.

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Posted by doctorwayne on Tuesday, August 22, 2017 12:13 AM

Track fiddler
...Strictly cosmetics and another negative aspect, not so much.....

Much of what we do in this hobby is cosmetic.  Smile, Wink & Grin  

I viewed superlevation as a positive rather than a negative, as trains do look good leaning into curves and just as good straightening up as they come out of the curves, too.  Most of my mainline radii are 34" or larger, and most of the layout is on curves and 2.5% grades, usually at the same time.  Trains are normally only 12 or 15 cars, but I have run ones in excess of 70, and never an incident of stringlining due to superelevation.
The only incident of stringlining I've ever experienced on my own layout was a long-ish train on a superelevated curve, but was caused by a minor derailment near the rear of the train, which in-turn caused that car's coupler to catch on a bridge guard rail.  The loco's engineer Embarrassed was unaware of the mishap  (and the crew in the caboose were too far back to see things go wrong), but when cars started toppling off the high bridge, the break in the air set the trains brakes - probably a good thing, too, as the locos, were in an area with no scenery at all, so it would have been a  54" drop, on either side of the track, to the concrete floor.

Here's some of the carnage that did occur...

Maybe if I had had the trees in place on the hillside, things might not have been so bad.  Luckily, there was no water in the Speed River, either, so no environmental issues at all. Stick out tongue

Because I used cookie cutter roadbed (3/4" plywood on risers) not only was the superelevation easy to add, it also automatically formed the easements into and out of the superelevation.  If you're doing it using shims, I think that it can be done, but not as easily nor likely as smoothly.

Here are two very short videos that sorta show the effect...

Wayne

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Posted by selector on Tuesday, August 22, 2017 12:22 AM

Track fiddler

...

I am just after smooth operation and trains not falling off the tracks.

A noble cause, believe me.  It is for most of us, and probably should be foremost for those new to the hobby and track-laying. So, I'm happy to see you spell out this priority; it's a great one.  You can always experiment with super-elevation later.

Track fiddler

Even with 2% grades and 18 inch radius N scale (very mild).  I am hesitant about adding a third variable of super elevation now...

Wise, and quite understandable. Again, you can always 'upgrade' or 'improve' or just add that other dimension some time once you know you can lay smooth tracks with zero derailments.  Going from level tracks to those on a grade takes some doing as well, especially if the grade is going to have to be fairly steep.  It requires a transition curve, a vertical curve, so that the couplers don't dig into the ties and don't come uncoupled. It's even trickier on curves, and worse if it all has to be superelevated because you want that look to it. 

 

Track fiddler

Just better off to leave well enough alone.

Do you think ?  I do respect your opinion.

 

I couldn't agree more.  For now, simple and effective is the way to go.  In time, you'll probably want to tinker and try super-elevation, and when that works reliably (no derailments whether trailing or shoving cars), you can try laying all of that on a vertical transition curve at the same time.  It keeps us on our toes in the hobby.Stick out tongue

I wish you happy successes as you go along.

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Posted by Track fiddler on Wednesday, August 23, 2017 5:40 PM

Funny stuff doctorwayne.  My condolences to your Railroad disaster.  Thank God nobody was hurt.  I didn't see a caboose laying amongst the boxcars, so everyone must be okay.

The double high bridge scene is quite impressive.  I do like looking at your work.  Very nice.

I do agree that super elevation cosmetics look good.  I also believe HO scale has twice the weight and twice the size wheel flanges than N scale does.  Seems to me that's got to have an advantage.

Thanks

 

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Posted by Track fiddler on Wednesday, August 23, 2017 5:53 PM

Selector thank you for getting back to me and the positive reinforcement.  

I think you made it easier for me to confirm my decision to hold off on superelevation for now.  I'll work on other things as I have plenty to do.

It's kind of funny, I never thought of the common sense of the matter.  Like you said I can always experiment and fiddle with super elevation later.

Thanks

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