Modelling Super-elevation on Curves

 
  Picton Locomotive Driver

Guys,
What's your view on super-elevation for curves on your layout?. Do many of you model this? If you, do how do you go about it? I've been experimenting on my layout but I can't seem to get the transition right from level to the super-elevation on the curve so I'm wondering if its worth the trouble. Most layouts I've seen don't seem to model this feature so I'm interested to see if anyone has done it and how they achieved this.

Cheers
Rob

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  SAR523 Assistant Commissioner

Location: Chicago, IL
I had them on my last layout and intend to do so again. While somewhat exaggerated for my prototype I think the trains look great visibly leaning into the curve.

I used thin strips of masking tape (say three strips from a normal width roll of tape) under the outside rail to elevate the track on approx 750mm curves.

I started each new layer about 25-30cm in from the last to smooth of the transition and went to 4-5 strips (from memory) on two 180 degree-ish curves. For smaller angles, I'd just start on the tangent track. But I wouldn't recommend elevating turnouts.

I found this method much easier than styrene shims and other methods. The tape provides a firm base for the rail so there's no sagging; the only problem is that it takes more ballast to fill in the track so get something cheap to fill it in a little (a good idea if you're using nicer ballast anyway).
  linton78 Train Controller

Location: South Coast NSW
Hey Rob,

Hope you're doing well.

On my last layout my Uncle came up with a pretty good way to super elevate curves.

It is easier to use on open type framework baseboards.

This may be hard to explain in words.

On the ends of the layout the baseboards are opened framed. A 180 degree curved baseboard was cut out of a sheet of 15 mm ply which was wide enough for a dual main line. This piece of baseboard is just like how you would cut out your baseboard sections for a helix. It just looked like a big U, 120 mm wide. I hope that makes sense.

The big U was then cut with a jigsaw up the centre, between where the two track would be laid. The cut did not go through at the ends. The ends sections of the U were still in one piece.

The big U was then placed on the open framework and the end sections were secured. Small shims were made up (I can't remember the thickness) and placed under the mid way point of the big U base board. A shim was placed under the outer side of each road section (as it had been split). Once the shim was in place the two baseboard sections were screwed down to the framework. This placed each split section of curved baseboard at a slight angle (super elevation). The neat part about this is that the superelevation transitioned nicely from the secured end sections (not split) to the maximum angle at the mid way point of the curve, determined by those first shims. Shims of lessening thickness are then inserted under the track base as you reach the end points of the curve and the curved base board secured.

Basically, this method uses the natural twist in a timber base board section to create the super elevation transition, rather than shimming directly under the track it's self. It tends to keep everything smooth.

We had no problems with running trains and it looked great.

Wow, sorry for that hugely confusing rant.

Linton
  LaidlayM Chief Commissioner

Location: Research
Does your prototype have super elevated track?  

Mark
  Gwiwer Rt Hon Gentleman and Ghost of Oliver Bulleid

Location: Loitering in darkest Somewhere
Super-elevation or cant is found on the real railway and is not hard to represent in model form.  Suitably done it can be very effective but it is easy to overdo.  It should be so subtle that it is barely noticeable rather than having the tracks akin to speedway turns!

My main layout is OO scale laid in Peco code 100 rail though the technique can be used for all popular scales and any track.  All the sharper curves are canted including canted reverse-curves which have to be done rather more carefully to avoid creating a twist in the track which derails stock or leads to uncoupling.

I slip a shim of scrap Plasticard beneath the sleepers on the outer rails, nothing more, which elevates them just enough to impart a slight cant.  At the mid-point of some curves I have used two pieces one on top of another to further increase the cant and create the effect of a transition into and out of maximum deficiency.

For the reverse-curves there is a shim beneath the mid-point of each curve but I allowed the track to take its natural flex through the transition from one direction to the other.  It therefore transitions nicely from (for example) a right-hand curve with the left rail raised through to a left-hand curve with the right rail raised.

When treating multiple tracks it is important to remember that each track has its own low and high points - the whole is not on one continuous slope but rather the inner rails of each track will be at the same level and the outer rails of each track at the same (but slightly higher) level.  A small step in the ballast can also be represented to make this more apparent if desired although in model terms the difference of 1mm or so might be regarded as too small to bother with.  The tighter the curve the greater the cant and the more apparent the step in the ballast however.

On my layout the effect is twofold.  First it looks realistic; second it does as it should and eases the passage of trains through curves.

It's hard to capture the effect in one photo but the view below shows the left-hand track is canted through the right-hand curvature and then - just discernible - the curve and cant are reversed mid-way along the platform.  The right-hand track is also canted but the difference in levels and a small step in the ballast can be seen clearly at the front end of the railcar.

  oscar2 Locomotive Fireman

I experimented with 1mm balsa sheeting on my temporary layout a few years ago. The baseboard was MDF, not ideal I know, but the curves were pinned down on the inner rail directly to the baseboard then the balsa sheet was placed underneath the outside rail and the curve was marked with a pencil. I'd remove the balsa, roughly cut curved strips about 5mm wide with scissors and glue them down with PVA under the edge of the sleepers. The strips started from about 30cm away from the end of the straight so a slight transition between flat and cant naturally occurred. The floating outside rail between the start of the balsa and the straight was then lightly packed with fine ballast that was then soaked in 50/50 water and PVA glue.  When the rest of the ballast was brushed on the whole curve and glued in the same way I thought the effect was pretty good and the ballast was solid in supporting the track and the PVA wash over the balsa hardened it too.

Not only was there super elevation but a transition curve as well. In my planned layout I'd like to give reverse curves the same treatment.
  viaprojects Chief Train Controller

If you, do how do you go about it?
Picton
if you wish to do the easy option look up kato track. they have the Easement track and Superelevated (banked) Curved Track.

http://www.katousa.com/HO/Unitrack/g-concrete.html
  Picton Locomotive Driver

Hey Rob,

Hope you're doing well.

On my last layout my Uncle came up with a pretty good way to super elevate curves.

It is easier to use on open type framework baseboards.

This may be hard to explain in words.

On the ends of the layout the baseboards are opened framed. A 180 degree curved baseboard was cut out of a sheet of 15 mm ply which was wide enough for a dual main line. This piece of baseboard is just like how you would cut out your baseboard sections for a helix. It just looked like a big U, 120 mm wide. I hope that makes sense.

The big U was then cut with a jigsaw up the centre, between where the two track would be laid. The cut did not go through at the ends. The ends sections of the U were still in one piece.

The big U was then placed on the open framework and the end sections were secured. Small shims were made up (I can't remember the thickness) and placed under the mid way point of the big U base board. A shim was placed under the outer side of each road section (as it had been split). Once the shim was in place the two baseboard sections were screwed down to the framework. This placed each split section of curved baseboard at a slight angle (super elevation). The neat part about this is that the superelevation transitioned nicely from the secured end sections (not split) to the maximum angle at the mid way point of the curve, determined by those first shims. Shims of lessening thickness are then inserted under the track base as you reach the end points of the curve and the curved base board secured.

Basically, this method uses the natural twist in a timber base board section to create the super elevation transition, rather than shimming directly under the track it's self. It tends to keep everything smooth.

We had no problems with running trains and it looked great.

Wow, sorry for that hugely confusing rant.

Linton
linton78
Hi Linton,
Thanks for the response....and confusing it wasn't. And I confuse easily!! You Uncle's solution looks good for a 2 track mainline which is exactly what I need for the bottom deck. As I suspected, I think there'll be a combination of techniques to get this right.

I'll let you know when it's operating so you can bring 5708 round for a run Wink

Cheers,
Rob
  Picton Locomotive Driver

Does your prototype have super elevated track?  

Mark
LaidlayM
Hey Mark,
Yes it does. Good old NSWGR in HO scale and when I say old, I mean 1930's old so yes, it's important I feel. Just need to work out the best methods.

Cheers
Rob
  Picton Locomotive Driver

Thanks Everyone for your replies and advice. I'm hand laying my track so the commercial offerings are not going to work....thanks anyway Viaprojects. I like all of your methods for super elevating and I think the way forward will be to give each a go and see what works best. I have a combination of 2 track and single track mainline so Gwiwer, your comments on multiple tracks having different high and low points and not overdoing the cant are important.

Again, thanks Gents, looks like I have some experimentation to do.

Cheers
Rob
  Picton Locomotive Driver

I had them on my last layout and intend to do so again. While somewhat exaggerated for my prototype I think the trains look great visibly leaning into the curve.

I used thin strips of masking tape (say three strips from a normal width roll of tape) under the outside rail to elevate the track on approx 750mm curves.

I started each new layer about 25-30cm in from the last to smooth of the transition and went to 4-5 strips (from memory) on two 180 degree-ish curves. For smaller angles, I'd just start on the tangent track. But I wouldn't recommend elevating turnouts.

I found this method much easier than styrene shims and other methods. The tape provides a firm base for the rail so there's no sagging; the only problem is that it takes more ballast to fill in the track so get something cheap to fill it in a little (a good idea if you're using nicer ballast anyway).
SAR523
Hi SAR523,
I just knew super elevating points was BAD. Problem is, I've got a 2 on  a 36" curve (914mm) and another 2 on a much larger radius (have still to work out the radius) so I'm suspecting that these curves don't get the cant treatment? Did you try canting with points and it went horribly wrong? Problem is, if I don't super elevate the curves with points, it will make these curves stand out against the rest.

Cheers,
Rob
  Gez Beginner

I used two different brands of cork with the thicker (3mm generic hobby shop made) on the outside and a thinner (AMRI brand) on the inside. Then with a sanding block sand the cork (which I would have done on flat staight track anyway) to get a perfect evan slant. It doesn't take a lots of sanding as the cork is relatively soft and you can ease in to the elevation gently.

Looks awesome on a 1200 mm radius curve with a Pacific and 14 coaches at full speed.
  hosk1956 Deputy Commissioner

Location: no where near gunzels
I personally don't like or see a need for super elevation in model form, in my experience it has led to other problems, but that is my choice, yours is yours.
An interesting issue was at my club track which I always thought was over elevated, my SAR Steel Cars (BGB models) fitted with American Limited diaphragms kept derailing on the curves, we could not find the problem for a long time, it turns out that as the coaches leaned into the curve, the inside top corners of the diaphragms bound up when the couplers were stretched to their max and basically lifted the bogies of the track. I had been striving for good close coupling.
The other interesting phenomena was that - as those who have these BGB Models Steel Cars know, are extremely top heavy, before I fitted the diaphragms they would fall over on the curves! Elevation gone, no more issues.
What probably also made ours an issue was that we had a reverse curve and the transitions were too short.
My opinion - don't bother but if you must I wouldn't go any thicker than 1mm.

Wayne
  Gwiwer Rt Hon Gentleman and Ghost of Oliver Bulleid

Location: Loitering in darkest Somewhere
Do not cant points.  That way madness lies!

I know of no way in which it is possible to super-elevate the curved route through a point whilst having the straight route dead flat.  Aside from which with proprietary track there are no flexible points to take up the cant and there will be problems with blades contacting stock rails securely and reliably.

But you can deal with the curve leading into or away from the point.

At one spot on my layout I have a double-track junction on a gradient and with the curved route leading off to the run-through fiddle yard.  Some trains therefore get routed that way to by-pass a station if shunting is in progress there.  The question of how to lay the track satisfactorily at the location vexed me for a while given that I not only have the gradient to consider but would like trains to take the turnout at line speed meaning cant is desirable.

As it happens the main line comes out of a long sweeping right-hander as it comes down-grade and that is canted.  It becomes straight before the junction but the dynamic of moving trains mean that anything routed into the yard, which is a right-hand divergence, have a tendency to follow the curve they have recently negotiated to the extent that they happily take the turnout which is not super-elevated but then run onto a short length of curved plain track which is.

Likewise trains exiting the yard to the main line do so by a canted left-hand bend before running through a non-canted point to the straight and then into the sweeping and canted left-hander as they climb away.
  Marbelup Station Master

Location: Perth, Western Australia
I was given some info by an older civil engineer when I worked at Westrail in the early 1990's, that the Westrail standard was for a maximum 100 mm cant on standard gauge and 75 mm on narrow gauge.

I have included cant and transitions on my Sn3.5 layout using the 75 mm figure which would be equivalent to 100 mm in HO due to the scale difference (both using 16.5 mm gauge track).

I have done it purely for appearance and I didnt expect any operational benefits from the cant, although there are benefits from the associated transitions.

I have had some minor operational problems, mainly with visiting rollingstock which either had inadequate allowance for rocking motion in the bogies and/or had a heavy roof which made them top heavy.

I had a curious problem with one of a rake of 5 coaches which I made as a "quickie" project using a printed card overlay on a length of pine timber.  It tended to overturn to the inside at a particular location at low speed.  I eventually determined that the density of the pine was not uniform and the coach was unbalanced.  I cured the problem by added some lead under the coach on the light side to restore the balance.

My layout has sub-roadbed of 9 mm ply and roadbed of 9 mm MDF with handlaid track.  I laid the curves "flat" then added the cant later by inserting short lengths of stripwood under the outside edge of the roadbed.  The roadbed is secured by screwsfrom below, so I was able to loosen the screws to install the stripwood and also make minor adjustments if needed before I added scenery and ballast.
  Gwiwer Rt Hon Gentleman and Ghost of Oliver Bulleid

Location: Loitering in darkest Somewhere
A short clip of the reverse-curve with a train running through.  Just enough cant to show that it's there and with a transition through level track beneath the footbridge.  The transition is also apparent on the train itself.  Click to play.

[img]http://gwiwer.smugmug.com/photos/i-kRV7D6z/0/L/i-kRV7D6z-L.jpg[/img]
  SAR523 Assistant Commissioner

Location: Chicago, IL
Hi SAR523,
I just knew super elevating points was BAD. Problem is, I've got a 2 on  a 36" curve (914mm) and another 2 on a much larger radius (have still to work out the radius) so I'm suspecting that these curves don't get the cant treatment? Did you try canting with points and it went horribly wrong? Problem is, if I don't super elevate the curves with points, it will make these curves stand out against the rest.

Cheers,
Rob
Picton
You can always just elevate the parts of the curve that are clear of turnouts (and probably not get to the same level of elevation). Or you can just leave them not elevated.  I don't think it'll greatly detract from the visuals of your layout.  Unless you really get the track elevated, the effect is subtle at best; you're more likely to notice when its present than that it's absent.

You can always mock up an elevated turnout to see why it's not a good idea.
  BladeHunter Station Master

Location: Sydney
That's some real nice work Gwiwer, even without the cant it would still be some real nice work.
  Picton Locomotive Driver

You can always just elevate the parts of the curve that are clear of turnouts (and probably not get to the same level of elevation). Or you can just leave them not elevated.  I don't think it'll greatly detract from the visuals of your layout.  Unless you really get the track elevated, the effect is subtle at best; you're more likely to notice when its present than that it's absent.

You can always mock up an elevated turnout to see why it's not a good idea.
SAR523
Thanks SAR523. I don't think I'll bother elevating the curves with the 2 points that have a very large radius as I don't think you'll notice as the viewing point has with the cant leaning towards you. The other one though, I think I'll elevate beyond the point. This point actually serves as part of the transition for the curve so I think it should look ok. As you say it should be subtle, much like in Gwiwer's clip in another post.

Cheers,
Rob
  Picton Locomotive Driver

A short clip of the reverse-curve with a train running through.  Just enough cant to show that it's there and with a transition through level track beneath the footbridge.  The transition is also apparent on the train itself.  Click to play.

[img]http://gwiwer.smugmug.com/photos/i-kRV7D6z/0/L/i-kRV7D6z-L.jpg[/img]
Gwiwer
That is very nice work Gwiwer. Very subtle cant which looks in proportion and enhances the movement of the train through the 'S' curve.

Cheers,
Rob
  Gwiwer Rt Hon Gentleman and Ghost of Oliver Bulleid

Location: Loitering in darkest Somewhere
That is very nice work Gwiwer. Very subtle cant which looks in proportion and enhances the movement of the train through the 'S' curve.

Cheers,
Rob
Picton

Thank you kindly.

Amazing what can be achieved with a few scraps of Plasticard!

I was told by a couple of very seasoned modellers long after the layout was built that two things in that view were very difficult to achieve.  One was effective cant and the other was building a station on an S-bend.

As i built the lot with no previous experience or knowledge I problem-solved for myself as I went along and what you see is the result. I leave it to everyone to form their own opinions.

If there's more interest in the layout (which is a 34 metre circuit) a link is in my signature.  Pictures and limited discussion also appear here https://www.facebook.com/penhaylebay

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