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I was wondering if anybody had any advice or knew of any articles or info on laying track with a realistic camber on bends. I saw the Carstairs layout at the weekend with a nice camber and it really helps

Adj
 

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I think the BWWMRC's Horton layout uses a triangular cross section layer of cork matting to achieve the required effect. Have a look at the relevant standard's here to see what the angle of cant should be.

Regards,

Dan
 

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QUOTE (adj @ 20 Mar 2007, 09:41) <{POST_SNAPBACK}>I was wondering if anybody had any advice or knew of any articles or info on laying track with a realistic camber on bends. I saw the Carstairs layout at the weekend with a nice camber and it really helps

Adj

I'm attempting this in N gauge by putting a strip of suitable thickness under one side of the track - I don't think it matters too much what the strip is made of. There's a recommended maximum in one of the MOROP documents (http://www.morop.org/en/idf/index.html) but the most important thing IMHO is to make sure all your stock can take the transition between flat/straight and canted/curved track without derailing. I intend to apply cant to one curve with the rest of the curves temporarily laid flat, so I can do a great deal of test running before canting the rest of the curves.

Incidentally 'camber' belongs somewhere in highway engineering, if you are talking about railways the term is 'cant'. There's a fair amount of 'cant' on the subject over on MREMag at present too!
 

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Discussion Starter · #4 ·
Thanks guys. Explains why I couldn't find any relevant documentation on the net. I've altered the topic title accordingly.
 

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QUOTE (Edwin @ 20 Mar 2007, 10:31) <{POST_SNAPBACK}>I'm attempting this in N gauge by putting a strip of suitable thickness under one side of the track - I don't think it matters too much what the strip is made of. There's a recommended maximum in one of the MOROP documents (http://www.morop.org/en/idf/index.html) but the most important thing IMHO is to make sure all your stock can take the transition between flat/straight and canted/curved track without derailing. I intend to apply cant to one curve with the rest of the curves temporarily laid flat, so I can do a great deal of test running before canting the rest of the curves.

Incidentally 'camber' belongs somewhere in highway engineering, if you are talking about railways the term is 'cant'. There's a fair amount of 'cant' on the subject over on MREMag at present too!

I was thinking along the same lines, placing a spacer under the sleepers on one side. The cant doesn't have to be too much, just as long as it works visually i'm happy. My concerns are how do you get a nice transition from the flat, is it necessary to compensate for clearance and so on.
I plan on using templot. I don't know if templot accounts for cant in curves so i'd need to place the plan on the flat surface, as if it were a projection of the track, place either a strip or a wedge under the sleeper on the outside of the curve and then once happy fill with ballast and glue it.

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I don't have any knowledge of Templot, but my limited experience so far suggests that the transition is critical. You may need to make a set of shims from various thicknesses of Plastikard and place them at intervals, but it's probably a case of trial and error rather than any hard and fast rule. The worst case vehicle is probably the longest rigid wheelbase you have (in my case a VGA van) but I'd strongly recommend making sure everything runs perfectly before ballasting it. I'm using the Noch pre-ballasted underlay so relatively easy to adjust the cant after the track is laid.

The Group Standards will give you maxima for cant (6" if I recall, which is twice what MOROP recommends for models). There are formulae for calculating the required cant but they are meaningless on a model because if our curves were scaled up to real life they would be limited to 5mph or completely forbidden. So probably a case of picking something that looks right and works!
 

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I sometimes sound like a sales rep. from Tillig, but unfortunately I'm not. I have these banking strips which I will be adding to the curves of my mainline when it gets laid in the near future (hopefully)


I bought them from Lokshop.de.
 

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Discussion Starter · #8 ·
QUOTE (Edwin @ 20 Mar 2007, 12:16) <{POST_SNAPBACK}>I don't have any knowledge of Templot, but my limited experience so far suggests that the transition is critical. You may need to make a set of shims from various thicknesses of Plastikard and place them at intervals, but it's probably a case of trial and error rather than any hard and fast rule. The worst case vehicle is probably the longest rigid wheelbase you have (in my case a VGA van) but I'd strongly recommend making sure everything runs perfectly before ballasting it. I'm using the Noch pre-ballasted underlay so relatively easy to adjust the cant after the track is laid.

The Group Standards will give you maxima for cant (6" if I recall, which is twice what MOROP recommends for models). There are formulae for calculating the required cant but they are meaningless on a model because if our curves were scaled up to real life they would be limited to 5mph or completely forbidden. So probably a case of picking something that looks right and works!

I found a document under the following page:
http://www.morop.org/en/normes/nem114_en.pdf

For 00 gauge they recomend ellavating the outside rail no more than 1mm higher than the inside rail maintains a constant height (not considering climbs or decents) so the sleepers on the inside will have to sink below the track bed level. Hope that makes sense, if not read the article!
 

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QUOTE (dbclass50 @ 21 Mar 2007, 08:17) <{POST_SNAPBACK}>That's the correct term I understand. (I await correction).

'Superelevation' is used in the MOROP standard, also in some international standards for the real railway, and 'crosslevel' is also used, but railway engineers in the UK are most likely to call it 'cant'.
 

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This MRF reference contains links to some interesting tools/calculators etc
Prototypical Transitions

Super elevation really is the proper term, being quite specific in what it means.
Cant has more than one meaning, further compounded by English North/South accent differences, but we'd better not go there.
 

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QUOTE (adj @ 20 Mar 2007, 19:41) <{POST_SNAPBACK}>I was wondering if anybody had any advice or knew of any articles or info on laying track with a realistic camber on bends. I saw the Carstairs layout at the weekend with a nice camber and it really helps

Adj

Adj,

Cant (camber is a road terminology) is a complex subject. I have installed it on all of my curves:

http://www.brma.asn.au/Files/Gallery/Model...315E%201280.jpg
http://www.brma.asn.au/Files/Gallery/Model...320E%201280.jpg
http://www.brma.asn.au/Files/Gallery/Model...321E%201280.jpg
http://www.brma.asn.au/Files/Gallery/Model...337E%201280.jpg
http://www.brma.asn.au/Files/Gallery/Model...341E%201280.jpg

These are 5 foot radius curves.
The track bed is 5mm ply with a strip of mdf under the outer edge of the curve. Both tracks reside on the same bed and are therefore in the same plane. It is more prototypical to place parallel tracks in their own plains, but unfortunately, we don't have the benefit of flexibile suspension on our models to cope with crossovers between two different planes.
The maximum permissible cant deficiency (difference between rail top levels) in the UK is 6 inches which is 2mm on our models, so you don't want to lift a curve up too much. It is all about giving an indication of cant and not overdoing it.

'Superelevation' is a US/Australian term. The correct term in the UK is Cant.

The length of track between a canted curve and straight track is know as a transition and this involves one of two calculations: a cubic parabola or a clothoid. The latter is very involved (I used the prototype MOSS and SCRAPS systems to calculate clothoids on my layout - you really need a computer to do them) and for the purposes of what we are doing, the cubic parabola is sufficient, indeed, MS Excel will do this for you!
Templot will calculate a transition for you in the horizontal plane, but I am not aware that it will calculate cant which is in the vertical plane.
A curve does not suddenly join to a straight on real railways. Through the transition, the radius changes according to one of the above formulea, from straight where the radius is large to the curve radius where the transition ends. It is this which gives the 'sweeping' effect:

http://www.brma.asn.au/Gallery/Plowmang/005.jpg
http://www.brma.asn.au/Gallery/Plowmang/007.jpg

005 above shows one of my transitions. A transition must be at least 1 foot long and/or longer than your longest vehicle (eg MKIII coach). The reason for this is that the cant must wind down through the transition from full cant to none at all. As above, we don't have suspension to be able to cope with twists in the track bed so you need to make this adjustment gently.

007 above shows a reverse transition. The curve in the foreground is 5 foot radius. The slips on the mainline are on the level and the curves beyond are about 9 foot radius IIRC. The curves are all canted and there are fully implented transitions.
Note that canting is not used in sidings of non-passenger lines although a goods line which was formerly a passenger line may well have cant. Canting is a requirement on passenger lines in the UK and under most railway administrations around the world.

Hope this helps,

Graham Plowman
 

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Hi Graham,

Thank you for an informative, comprehensive yet easy to understand guide on how canting/superelevation should be applied in the hobby.


BTW - you should be proud of your modelling skills.


Kind regards.

Johan
 

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Excellent - I just wish I had that sort of space available.



Regards

John
 

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Those pics are absolutely SUPERB - never seen better, ever!


But, to clarify the super-elevation/cant confusion:
"Super-elevation" has an absolutely specific meaning - it is the difference in relative HEIGHT between the higher and lower rail.
"Cant" (apart from non-engineering meanings) means the ANGLE produced by that super-elevation.

For example (assuming standard gauge track of 56.5 inches)
One might require a cant of 3 degrees.
That calculates to a super-elevation of 3 inches

Using small imperial figures as in that example, it can readily be seen that the numbers are near enough the same and hence the casual substitution of terminology: admittedly a lot easier to write cant than super-elevation!


Nevertheless, they are not the same UNITS and this becomes immediately obvious when larger numbers are used.
For instance, if one requires a cant of 45 degrees,
then one requires super-elevation of 56.5 inches.
The numbers are now a long way apart and cannot be substituted.

One may justifiably say, those are unrealistically high figures in practice - so let's go a stage further.
UK has been officially metric for a good number of years.
Reverting to the first example, we now require a super-elevation of 75mm to produce a cant of 3 degrees.
The figures of 75 and 3 are now obviously far from interchangeable and hence the real need to use unambiguous terms.

In summary
Super-elevation is the difference in rail height, expressed in whatever units one desires.
Cant is the slope produced by that super-elevation, normally expressed in degrees.

No denying the casual practice of UK in using the 4-letter 'cant' interchangeably, but it has always been ambiguous and, in world terms, out of step and plain wrong.

UK is gradually (and largely unwillingly!) being dragged into the modern age of International Trade and International Standards.
Many examples of confusingly ambiguous UK practice being forced into line with World Standards can be found in the following British Health and Safety Executive document.
HSE - Railtrack . . .
It is a large document - the section dealing specifically with super-elevation starts on page 23. It uses "Super-elevation" as standard with (cant) in brackets to keep the old guard in touch!

If you have the time and interest, iit makes a fascinating and highly informative read, very well illustrated with clear diagrams throughout. It touches on many other subjects that come up on the forum apart from this one.

I found it particularly interesting that "turnout" is adopted as the unambiguous term for what have variously been called points and switches in the past.
Not before time!
 

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A bit of pedantry for a Friday afternoon:

Network Rail's Track Design Handbook (February 2007) uses 'cant' most often, and defines it as being the height of the centreline of one rail above the other, with 'superelevation' and 'crosslevel' stated to be identical meaning to 'cant'. 'Superelevation' is however used on its own a couple of times.

So the definition of superelevation as the height difference and cant as the angle doesn't appear to stack up with UK usage. I don't see that there is any problem with either term being used in either context provided the user quotes inches, millimetres or degrees.

Whatever it is called, both Network Rail and international standards state that the height distance is measured at the centrelines of the rails, not the gauge faces. So the 56.5 inches used by the previous poster should actually be a bit greater, but how much greater depends on the rail profile! Quoting the angle would be much less confusing.

And to get really silly, Network Rail thinks 'superelevation' is one word, HSE (as linked from the previous post) thinks it is two words and the previous poster thinks it is hyphenated. We like standards so much we have three of them...
 

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QUOTE (Edwin @ 23 Mar 2007, 16:17) <{POST_SNAPBACK}>A bit of pedantry . . .
And to get really silly, Network Rail thinks 'superelevation' is one word, HSE (as linked from the previous post) thinks it is two words and the previous poster thinks it is hyphenated. We like standards so much we have three of them...

Actually I though it was quite a LOT of pedantry!

And yes, on the silliness!
Actually I don't think it should be hyphenated - I was playing safe by quoting from page 23 of the HSE document.
Then I could blame them, if jumped on!
Other than that, I would normally use a single word, but truth is, I'm not quite sure!
 
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