# Track Camber for garden rail



## chrisatpassare (Jun 23, 2021)

I am interested in making a layout in my garden. I have a space 20m by 5m so I can accommodate an R5 radius at one end and an R3 at the other. My question for the track support construction is what reasonable cambers should apply to these two radii.
Chris


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## Pete Thornton (Jan 2, 2008)

chrisatpassare said:


> what reasonable cambers should apply


I think if you look around here at the various videos of steam-ups or other activity you will notice a complete lack of camber (or super-elevation as it is called in the USA.)
New layout in Ardèche

Unless you want to go really, really fast, it may be too much trouble.


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## Greg Elmassian (Jan 3, 2008)

Most model suspensions will not handle track warp, where the cross level varies. This is NOT superelevation, but poor track alignment.

You can use superelevation, but you need easements... typically in a layout, you go from straight to an immediate curve. In a real railroad the curve transitions from straight to max curvature.

This same transition, which is called an easement, is needed in the vertical dimension also when doing superelevation. If you look at how much track is needed to do these transitions, in almost all cases they are impractical for our layout sizes.

So bottom line most people cannot use superelevation.

But you CAN get rid of track warp / crosslevel problems, and you should, again since our models do not have a prototype suspension that can take these variations in track alignment.

Greg


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## chrisatpassare (Jun 23, 2021)

By camber i mean the slope across the rail to stop the train coming off the track at speed on th


chrisatpassare said:


> I am interested in making a layout in my garden. I have a space 20m by 5m so I can accommodate an R5 radius at one end and an R3 at the other. My question for the track support construction is what reasonable cambers should apply to these two radii.
> Chris





Pete Thornton said:


> I think if you look around here at the various videos of steam-ups or other activity you will notice a complete lack of camber (or super-elevation as it is called in the USA.)
> New layout in Ardèche
> 
> Unless you want to go really, really fast, it may be too much trouble.


Thanks Pete


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## chrisatpassare (Jun 23, 2021)

Greg Elmassian said:


> Most model suspensions will not handle track warp, where the cross level varies. This is NOT superelevation, but poor track alignment.
> 
> You can use superelevation, but you need easements... typically in a layout, you go from straight to an immediate curve. In a real railroad the curve transitions from straight to max curvature.
> 
> ...


Thanks Greg


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## Greg Elmassian (Jan 3, 2008)

If you really want to superelevate, I gather you are doing it for looks.

Here is an NMRA document that talks about the vertical easements for superelevation (they call transitions) 

If you follow these practices you will do well. Again, to do this right, you almost triple the length of grades/curves. It looks great, but to work well, you need a lot more space.

Greg


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## chrisatpassare (Jun 23, 2021)

Greg Elmassian said:


> If you really want to superelevate, I gather you are doing it for looks.
> 
> Here is an NMRA document that talks about the vertical easements for superelevation (they call transitions)
> 
> ...


Hi Greg, Thanks again, For looks, the train should lean as it goes around the bend. not much, not so much that it is unstable if it stops. I guess the superelevation is related to the average speed on the bends. I need to go back to my Physics classes! I imagine that the transition from straight to bend can be "forced"a bit in the track base. I can't see the document.
Chris


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## fredlub (Feb 7, 2010)

Pete Thornton said:


> I think if you look around here at the various videos of steam-ups or other activity you will notice a complete lack of camber (or super-elevation as it is called in the USA.)
> 
> 
> Unless you want to go really, really fast, it may be too much trouble.


I have super elevation on my garden layout but it is however not visible on videos:




I agree it might not be worth the trouble.
Regards
Fred


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## chrisatpassare (Jun 23, 2021)

fredlub said:


> I have super elevation on my garden layout but it is however not visible on videos:
> 
> 
> 
> ...


Hi Fred,
If you look closely you can see it on some of the bends. I am thinking of makingtwo long bends R5. How much super elevation did you add. Did you have a formula or something. Chris


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## chrisatpassare (Jun 23, 2021)

chrisatpassare said:


> Hi Fred,
> If you look closely you can see it on some of the bends. I am thinking of makingtwo long bends R5. How much super elevation did you add. Did you have a formula or something. Chris


Just a note about your trackbed: It looks like you made a metal tray filled with fine shingle ad laid the track in it. Or is the shingle just ballast?
Chris


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## Greg Elmassian (Jan 3, 2008)

Sorry about the link:



https://www.nmra.org/sites/default/files/d3b1.pdf



Greg


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## fredlub (Feb 7, 2010)

Hello Chris,
The rail is "floating" on the ballast/shingle with which the metal tray or gutter is filled.
I do not make the super elevation very scientific. A (smart) friend made a special vehicle with spirit levels at 90 degrees which I use for horizontal and vertical alignement. The vehicle is split in the middle so the two non sprung axles can move independently. The levels can be calibrated with the knobs beforehand on a level surface.








Regards
Fred


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## Pete Thornton (Jan 2, 2008)

Greg Elmassian said:


> Most model suspensions will not handle track warp, where the cross level varies. This is NOT superelevation, but poor track alignment.


While I agree with Greg, I should say rthat I try to make sure my locomotives and other equipment have some degree of suspension, as the average garden layout will have some side-to-side transitions, intentional or not. (Greg's does not, of course.) I spent some effort making the trucks on a Bachmann tender loose enough to allow the wheels/axles to rock indepentantly, as it derailed on less-than-perfect track. Most expensive brass/steel locs, like live steamers, have some degree of springing in the suspension, which may or may not work. Aristocraft tried mightily to make their long-wheelbase locos cope with such track, though not all their efforts were successful.


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## Greg Elmassian (Jan 3, 2008)

The problem is mostly the locos, where adding suspension to the drivers is beyond the capability of most hobbyists. Even some locos that are sprung don't actually work.

Actually, Aristo has a weird pivoting truck, that of all things, works well with track warp, since each driver module pivots along the long axis of the loco... who'd a thunk? (but they are terrible on normal vertical transitions). This is only in reference to the locos with the "prime mover" gearbox.

Greg


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## Pete Thornton (Jan 2, 2008)

Greg Elmassian said:


> since each driver module pivots along the long axis of the loco..


That was what I meant by not always successful. I was astounded that the axle modules do not allow any up/down movement over the wheelbase. And I've had several locos with springs that were much too stiff and stopped any movement.


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## Greg Elmassian (Jan 3, 2008)

Agreed, it was a real eye-opener to me, but if you really dissect a prime mover, and have followed it's evolution, you will see that it USED to have sort of a suspension, and also self-aligning capabilities.

Over the years, other issues caused Aristo to change the assembly process and actually remove a number of cleverly designed features. The easy to replace motor is gone, the self-aligning capability of the motors and gearboxes is gone. the small amount up up and down travel is gone. The unrestricted compliance to warped track is gone, and the power pickup system per axle is severely compromised.

Many of these things can be corrected, all documented on my site.

Greg


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