Superelevation
- Thread starter Jaime
- Start date
G-force1
Prevarication Rules!
Usually none or very little. It isn't easy to achieve, or maintain (nothing's impossible), also our speeds don't really require it. If you are bedding loose into ballast then the track will move about some so you can lose the effect. With rolling stock with no suspension there is the possibility for them to rock from corner to corner on entering the elevated curve and possibly derail.
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David1226
Registered
Superelevation implies the use of speed. To my mind that is the antitheses of model railways. I suspect the majority of G Scale, and certainly all of 16mm scale, run narrow gauge models. Prototypically these ran at slow speeds. There is nothing worse, in my book, than seeing a model train being run at an unrealistic speed. For that reason I am not a big fan of live steam. Apart from the recent introduction of Slo-Mo fitted locos you rarely see live steam being run at realistic slow speeds which totally spoils the effect. If main line express trains are your thing, then by all means use superelevation.
David
Rhinochugger
Retired Oik
Not necesselery
If you run entirely LGB stock, then with their deep flanges designed for their small radius curves, superelevation is not a necessity, but can sometimes look good (I'm thinking of one of the famous Thomas the Tank Engine railways on this forum).
However, if you're using locos and stock with a finer (not necessarily fine scale) flange, then sometimes a small degree of superelevation is necessary, particularly on 8 ft diameter curves to stop the locos derailing - doing the railway equivalent of the 'high step off'. Equally, superelevation on a longer sustained curve can sometimes avoid the 'stringing' problem of stock being pulled over.
Once you get up to 12ft diameter, I doubt there's any practical benefit
So I either pack the ballast, or on a solid base, slip a wedge of some sort under the sleepers
James Day
Guano Corner Rly - Runs weekly - Guano permitting
On real railways they use the term Cant for this. If you google up Cant Angle you get this:
inclination from a vertical or horizontal plane; slope; slant. 2. a sudden movement that tilts or turns something. 3. the angle or tilt thus caused.
On course scale model railways like G scale, this should really not be necessary at most speeds, given the over-scale flanges used, but before WW2 Hornby 0 Gauge curves all came on sloping sleepers!
James
inclination from a vertical or horizontal plane; slope; slant. 2. a sudden movement that tilts or turns something. 3. the angle or tilt thus caused.
On course scale model railways like G scale, this should really not be necessary at most speeds, given the over-scale flanges used, but before WW2 Hornby 0 Gauge curves all came on sloping sleepers!
James
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Rhinochugger
Retired Oik
Frank Gallagher
Well matured physically if not mentally
Did you spell that correctly?
Eeyore.Boater
Registered
The drawing also shows the rails inclined inwards on the sleepers, not seen that on any model track. I beleive the inclination mirrors the wheel profile and allows the wheel to roll on the centre of the railhead.
Neil Robinson
Registered
Whilst light railways were fairly slow not all narrow gauge lines fell within their remit, particularly if they pre-dated the Light Railways act.
According to this source
https://www.festipedia.org.uk/wiki/Tyler's_Curve
This line's tightest mainline curve had a 3.5 inch cant on a two foot gauge!
According to this source
https://www.festipedia.org.uk/wiki/Tyler's_Curve
This line's tightest mainline curve had a 3.5 inch cant on a two foot gauge!
Rhos Helyg Loco Works
Registered
An unsprung 4-wheel vehicle is likely to derail as the track twists to go in to an elevated curve, with the likelihood increasing with the wheelbase. Best avoided, I reckon.
Greg Elmassian
Guest
There are several issues with superelevation (what we call it in the colonies).
1. hard to "enforce" with our track free floating in ballast, normally it requires fixing the track to something, usually not a good idea.
2. In real railroads, there is normally an "easement" when going into a curve, i.e. you don't go directly from straight to a fixed radius curve. Well, now with superelevation, you have an ADDITIONAL curve to work with in a different plane, and you should again give an easement going into it... by the time you have this easement at the beginning and end of the curve, you have reduced the distance that shows the superelevation. Since you are doing this for appearance only, it reduces the visual impact.
3. many people have derailments due to problems with "cross level", i.e. level across the rails. Adding superelevation compounds this problem. The suspensions on our rolling stock and locomotives is just not a compliant as the real thing. Therefore you normally reduce the reliability of your railroad when doing this.
Greg
1. hard to "enforce" with our track free floating in ballast, normally it requires fixing the track to something, usually not a good idea.
2. In real railroads, there is normally an "easement" when going into a curve, i.e. you don't go directly from straight to a fixed radius curve. Well, now with superelevation, you have an ADDITIONAL curve to work with in a different plane, and you should again give an easement going into it... by the time you have this easement at the beginning and end of the curve, you have reduced the distance that shows the superelevation. Since you are doing this for appearance only, it reduces the visual impact.
3. many people have derailments due to problems with "cross level", i.e. level across the rails. Adding superelevation compounds this problem. The suspensions on our rolling stock and locomotives is just not a compliant as the real thing. Therefore you normally reduce the reliability of your railroad when doing this.
Greg
Rhinochugger
Retired Oik
I have a few curves which are superelevated, and they run just fine. You do have to be careful to have just the right amount.
On the WWNR, most of the superelevated curves are in ballast, and as I say, you just need to pack the ballast to get the cant. Only one of them is on the solid sleeper, and there's a small plastic shim at the appropriate place.
The Accy shay was the loco that first moved me toward this aspect of track laying - as it was not always enamoured with LGB R3 curves, but a little bit of superelevation, and she was as reliable as the rest
On the WWNR, most of the superelevated curves are in ballast, and as I say, you just need to pack the ballast to get the cant. Only one of them is on the solid sleeper, and there's a small plastic shim at the appropriate place.
The Accy shay was the loco that first moved me toward this aspect of track laying - as it was not always enamoured with LGB R3 curves, but a little bit of superelevation, and she was as reliable as the rest
If you went down the Cant route, I would suggest a Coffee Stirer on the outside rail of a curve would give sufficient effect. Less is probably more with all that has been said on this matter.
JonD
James Day
Guano Corner Rly - Runs weekly - Guano permitting
Neil,
I think the seemingly excessive Cant on the FR was to accomodate the speed of the gravity slate trains?
I have recollections of the cant also being in places where it really wasn't needed - such the main platform road at Harbour Station! No gravity trains ever went in there. I seem to recall reading that one went into the goods shed once, in error!
James
David1226
Registered
The foreman hit the roof
beavercreek
Travel, Art, Theatre, Music, Photography, Trains
The Accy shay was the loco that first moved me toward this aspect of track laying - as it was not always enamoured with LGB R3 curves, but a little bit of superelevation, and she was as reliable as the rest
Interesting point there Rhino.
Once, when I thought that all was well with my track as I was having no derailments..... but then there had been a few torrential storms. a friend brought over his lovely electric 'T' boiler Accy 2 cyl shay. All was well until it was negotiating a certain curve (10ft radius). Everything else (non-Accucraft) had gone around OK but it was only this particular curve that upset my friend's shay with its finescale wheels.
So out came the spirit level and the track level gizmo and low and behold the little bit of 'superelevation' that I had put in that particular place for my Accy kit, had been swept away by the rain (even after 6 years of being okay).
That 'problem area now has stone under the ballast and the ballast has been well and truly glued with exterior waterproof PVA (a system that I have rolled out (or should it be poured/sprayed) around most of the layout. 3 years on since the first glue deployment and it is still as hard as rock (I used particularly small gauge ballast as that stays glued the best.... and also looks good too)..
Moral is, ballast moves and keeping 'special' levels can be difficult as they are prone to be being 'altered' by weather, footfall, animals etc etc. So glue or cement is a good idea to keep it in place if you have to have one
Thomas Lambo
RC, wood craftsmanship & culinary arts
Very informative discussion....particularly to someone that's getting ready to lay their GR track