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Advices on choice of track please ...


rogerv
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I am designing a (8' x 4') layout from scratch after an absence from RM of 40 years !

 

I intend to use Setrack curves and straights for continuous running lines, with Streamline short turnouts for sidings and passing loops (all curves will be hidden, straights chopped down where necessary to account for Streamline points).

 

I think I am left with just one question ...​

 

I believe the track separations on the hidden curves will all be 67mm as a given of the fixed geometry, but I want to reduce this to 50mm for the straight running lines.  Is there any way I can achieve this other than by using flexi to make the transitions?

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Welcome to RMWeb Rogerv.

 

Let's say you start with a half circle of second radius curves.  If you then make a half circle of third radius curves outside of that then you will indeed have the constant set track spacing of 67 mm throughout the curve.  However, if you then replace the first and last of the second radius curves (ie the inside curve) with third radius (or fourth), then these third radius curves will effectively form a transition (albeit a curve of fixed radius rather than a true transition curve) and you will reduce the separation between the two lines to less than 67 mm.  However, I'm not sure by how much and whether third or even fourth radius curves would be better - you may need a bit of trail and error.  You'll probably still have to form transitions with flexible track to get to the exact Streamline spacing on your straights, but if you simply start your transition as a larger fixed radius curve, then you may find it easier to make a slightly shorter transition with the flexible track.

 

Good luck with the layout planning and I hope you enjoy getting back into Railway Modelling.

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I believe the track separations on the hidden curves will all be 67mm as a given of the fixed geometry, but I want to reduce this to 50mm for the straight running lines.  Is there any way I can achieve this other than by using flexi to make the transitions?

 

I believe you may be over-thinking this.  Have a look at this diagram, which shows turnouts formed from Streamline small radius points on each side of a half oval formed of Setrack curves:

 

gallery_23983_3473_3742.jpg

 

The separation on the straights is 52mm, which is what you get with crossovers formed from Streamline points.  The separation at the midpoint of the curve is 67mm, since that's what you get with Setrack curves starting with the rail ends level.  All that the mixed geometry results in is a 2 x (67-52) = 30mm gap at the midpoint of the inner curve, which you can fill with a cut down length of Setrack straight - no need for any flexi.  The curves may look a bit odd going from 52mm to 67mm track separation (though I'd suggest that it's not all that noticeable) but you've said that they'll be hidden anyway, so who cares?

 

You need to be a bit careful to avoid problems with stock clearances as the track separation reduces.  If you go for 3rd and 4th radius instead of 2nd and 3rd as I've drawn it then the risk would be lower.  That said, on my previous layout using 2nd and 3rd radius wasn't a problem:

 

med_gallery_23983_3473_25779.jpg

 

You can build more complicated configurations so long as you remember the angles used in the Streamline and Setrack geometries (primarily 12º, and 22.5º/45º), and you can do a bit of trigonometry.  Sines and cosines are all you need - I use a small Excel spreadsheet that I can plug track endpoint co-ordinates in to, and it tells me the length of straight track needed to fill the gap.  This is as an adjunct to AnyRail as my track planning tool.  Other programmes are available but I find AnyRail by far the easiest to use for this kind of layout design.  The functionality of each the others I've tried seems to be much more oriented towards the use of flexible track, which IMO just gets in the way when you actually want to stick to using modular track.  AnyRail can do flexible track (that's what the cut-down Setrack straights actually are in the diagram above) but other design tools are probably better if you're going for Streamline throughout.

 

By the way, I also use Setrack curves cut down to a 12º angle to form parallel sidings and the like in combination with Streamline points, although I try to avoid it other than for fans of sidings - where arguably flexi laid "by eye" can usually do the job just as well anyway.  You can use the Setrack ST238 "special curve" (intended to be used with the Setrack Y point) which is actually larger radius than the Streamline small radius points, but as the curve is only 11.25º you have to use two of them, eg both cut down to 6º, which is a bit of a bodge (though that doesn't mean that I don't do it if the need arises  :wink_mini:).

 

Remember to use code 100 Streamline points, so that they match the profile of the Setrack rail.  Unless you absolutely need electrofrog diamonds or slips, in which case you need either the SL-113 code 75 to code 100 converter track (which is the same length as the Setrack ST203 straight - "the totty wee one" as the lady in my local model shop calls it), or the SL-112 combined rail joiners.  I don't have any personal experience of either of those products so I can't say anything more than that they exist, I'm afraid.

 

There are quite a few other threads on RMWeb where combining Setrack and Streamline is discussed, eg here, here and here.

Edited by ejstubbs
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What ejs said .....or similarly, a bit of straight track at the 45o point on the inner track of a 90o curve.

 

Also, I would recommend using straight flexi rather than chopping down Setrack straights - cheaper too.

 

Chris

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I believe you may be over-thinking this.  Have a look at this diagram, which shows turnouts formed from Streamline small radius points on each side of a half oval formed of Setrack curves:

 

gallery_23983_3473_3742.jpg

 

The separation on the straights is 52mm, which is what you get with crossovers formed from Streamline points.  The separation at the midpoint of the curve is 67mm, since that's what you get with Setrack curves starting with the rail ends level.  All that the mixed geometry results in is a 2 x (67-52) = 30mm gap at the midpoint of the inner curve, which you can fill with a cut down length of Setrack straight - no need for any flexi.  The curves may look a bit odd going from 52mm to 67mm track separation (though I'd suggest that it's not all that noticeable) but you've said that they'll be hidden anyway, so who cares?

 

You need to be a bit careful to avoid problems with stock clearances as the track separation reduces.  If you go for 3rd and 4th radius instead of 2nd and 3rd as I've drawn it then the risk would be lower.  That said, on my previous layout using 2nd and 3rd radius wasn't a problem:

 

med_gallery_23983_3473_25779.jpg

 

You can build more complicated configurations so long as you remember the angles used in the Streamline and Setrack geometries (primarily 12º, and 22.5º/45º), and you can do a bit of trigonometry.  Sines and cosines are all you need - I use a small Excel spreadsheet that I can plug track endpoint co-ordinates in to, and it tells me the length of straight track needed to fill the gap.  This is as an adjunct to AnyRail as my track planning tool.  Other programmes are available but I find AnyRail by far the easiest to use for this kind of layout design.  The functionality of each the others I've tried seems to be much more oriented towards the use of flexible track, which IMO just gets in the way when you actually want to stick to using modular track.  AnyRail can do flexible track (that's what the cut-down Setrack straights actually are in the diagram above) but other design tools are probably better if you're going for Streamline throughout.

 

By the way, I also use Setrack curves cut down to a 12º angle to form parallel sidings and the like in combination with Streamline points, although I try to avoid it other than for fans of sidings - where arguably flexi laid "by eye" can usually do the job just as well anyway.  You can use the Setrack ST238 "special curve" (intended to be used with the Setrack Y point) which is actually larger radius than the Streamline small radius points, but as the curve is only 11.25º you have to use two of them, eg both cut down to 6º, which is a bit of a bodge (though that doesn't mean that I don't do it if the need arises  :wink_mini:).

 

Remember to use code 100 Streamline points, so that they match the profile of the Setrack rail.  Unless you absolutely need electrofrog diamonds or slips, in which case you need either the SL-113 code 75 to code 100 converter track (which is the same length as the Setrack ST203 straight - "the totty wee one" as the lady in my local model shop calls it), or the SL-112 combined rail joiners.  I don't have any personal experience of either of those products so I can't say anything more than that they exist, I'm afraid.

 

There are quite a few other threads on RMWeb where combining Setrack and Streamline is discussed, eg here, here and here.

 

Thank you so much - crystal clear!  Watch this space for my next silly question once I've firmed up all the track layout.  Will probably relate to incline gradients, tunnel mouths, and viaducts!

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Thank you so much - crystal clear!  Watch this space for my next silly question once I've firmed up all the track layout.  Will probably relate to incline gradients, tunnel mouths, and viaducts!

 

BTW, the inspiration for my design is the Settle to Carlisle (where else?), because I love all the civil engineering..

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You could cut the webs between sleepers on the curves and gently tweak the curves to a slightly larger radius. I have eased 2nd radius out to nearly 3rd radius doing this. Don't try to tighten the radius, I can't make that work without kinks.

On a small layout, for steam days, use set track long straights for straight sections as streamline is hard to lay dead straight and steam age tracks were dead straight.  Diesel era use second hand streamline as the dogs hind leg look is quite prototypical.

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Prompted by another thread, I just went and had a look at Shinohara's range of Code 100 set track and noticed that they do a much larger range of curvatures than the British manufacturers and their radii seem to be designed to give 2" track centres on curves. Whether this would provide enough clearance for your stock, and where you might obtain the range in the UK, however, I don't know.

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You could cut the webs between sleepers on the curves and gently tweak the curves to a slightly larger radius. I have eased 2nd radius out to nearly 3rd radius doing this. Don't try to tighten the radius, I can't make that work without kinks.

On a small layout, for steam days, use set track long straights for straight sections as streamline is hard to lay dead straight and steam age tracks were dead straight.  Diesel era use second hand streamline as the dogs hind leg look is quite prototypical.

 

 

Sorry, Dave, can't agree with this.  All railways, whatever era, lay track for the fastest possible running and the easiest gradients dictated by the geography and availability of land, and while the ideal way to do this is in a dead straight line, the 'line of least resistance is very often a gentle (and sometimes not so gentle) curve.  

 

There is a case for using setrack on a small layout with curves tighter than 24" radius due to the difficulty of laying Streamline to radii tighter than that and holding it to an accurate radius without losing the gauge, and that suggests straight sections between the curves if you want to keep the geometry simple.  Streamline is not hard to lay in long straights, you just line it up against a straight edge or draw a straight line to lay it to, but setrack straights are just as good!  But a gentle, flowing, curve between areas of pointwork or the sharper curves at the ends of the layout is prototypical for any era.

 

The dog's hind end look should be restricted to sidings and is better achieved by weathering and painting than using secondhand track unless you are 'scale' enough to consider fully compensated chassis.

 

My view is that I would not recommend using second hand track for any purpose to a beginner, as it is likely to be warped and twisted all over the place after lifting, and second hand pointwork is just asking for trouble.  Unreliable running is probably the thing most likely to sap a newbie's confidence and enthusiasm, and depends on trackwork smoothly laid and joined on level boards.  Our OP wants inclines and viaducts, an homage to the S & C, and needs to understand that the incline top and bottom must be a transition curve in a vertical plane, and if he using setrack, kept well away from curves or pointwork!

Edited by The Johnster
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Sorry, Dave, can't agree with this.  All railways, whatever era, lay track for the fastest possible running and the easiest gradients dictated by the geography and availability of land, and while the ideal way to do this is in a dead straight line, the 'line of least resistance is very often a gentle (and sometimes not so gentle) curve.  

 

There is a case for using setrack on a small layout with curves tighter than 24" radius due to the difficulty of laying Streamline to radii tighter than that and holding it to an accurate radius without losing the gauge, and that suggests straight sections between the curves if you want to keep the geometry simple.  Streamline is not hard to lay in long straights, you just line it up against a straight edge or draw a straight line to lay it to, but setrack straights are just as good!  But a gentle, flowing, curve between areas of pointwork or the sharper curves at the ends of the layout is prototypical for any era.

 

The dog's hind end look should be restricted to sidings and is better achieved by weathering and painting than using secondhand track unless you are 'scale' enough to consider fully compensated chassis.

 

My view is that I would not recommend using second hand track for any purpose to a beginner, as it is likely to be warped and twisted all over the place after lifting, and second hand pointwork is just asking for trouble.  Unreliable running is probably the thing most likely to sap a newbie's confidence and enthusiasm, and depends on trackwork smoothly laid and joined on level boards.  Our OP wants inclines and viaducts, an homage to the S & C, and needs to understand that the incline top and bottom must be a transition curve in a vertical plane, and if he using setrack, kept well away from curves or pointwork!

 

Thank you David.  Just wondering what an OP is - "old person" ?!  I have been assuming I would use the Woodland Scenics incline sets

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Sorry, Dave, can't agree with this.  All railways, whatever era, lay track for the fastest possible running and the easiest gradients dictated by the geography and availability of land, and while the ideal way to do this is in a dead straight line, the 'line of least resistance is very often a gentle (and sometimes not so gentle) curve.  

 

There is a case for using setrack on a small layout with curves tighter than 24" radius due to the difficulty of laying Streamline to radii tighter than that and holding it to an accurate radius without losing the gauge, and that suggests straight sections between the curves if you want to keep the geometry simple.  Streamline is not hard to lay in long straights, you just line it up against a straight edge or draw a straight line to lay it to, but setrack straights are just as good!  But a gentle, flowing, curve between areas of pointwork or the sharper curves at the ends of the layout is prototypical for any era.

 

The dog's hind end look should be restricted to sidings and is better achieved by weathering and painting than using secondhand track unless you are 'scale' enough to consider fully compensated chassis.

 

My view is that I would not recommend using second hand track for any purpose to a beginner, as it is likely to be warped and twisted all over the place after lifting, and second hand pointwork is just asking for trouble.  Unreliable running is probably the thing most likely to sap a newbie's confidence and enthusiasm, and depends on trackwork smoothly laid and joined on level boards.  Our OP wants inclines and viaducts, an homage to the S & C, and needs to understand that the incline top and bottom must be a transition curve in a vertical plane, and if he using setrack, kept well away from curves or pointwork!

 

 Thank you David.  Is an "OP" an "Old Person" ?!  Regarding inclines I have assumed I would use the Woodland Scenics products (lumps of polystyrene?) that would incorporate the necessary vertical transitions.  But you have put me on alert when you advise not to combine inclines with Setrack curves.  Why not?  I could shim the polystyrene blocks to provide superelevation if that is the problem ...  If my arithmetic is correct no grade would be more severe than 1:64 ...

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But you have put me on alert when you advise not to combine inclines with Setrack curves.  Why not?  I could shim the polystyrene blocks to provide super-elevation if that is the problem ...  If my arithmetic is correct no grade would be more severe than 1:64 ...

 

When I was a teenager back in the 1980s, my first layout was around 6' x 4', used Hornby track and had a bridge over another line with rather steep gradients either side, some of which was curved track and I had a point near the bottom of one incline.  I can't remember if it was first or second radius curves on the incline. The gradients were probably something like 1:25 and 1:30, which meant that the locomotives that I had, struggled with anything more than two coaches.  As such, that layout didn't last long and was soon broken up in favour of a 'shelf' along the wall of my bedroom.  I've never considered gradients since.

 

With more gentle gradients, haulage should be less of an issue and you should manage more than two coach trains.  However, when using set-track curves, you'll find that with a decent length train, you will have the locomotive travelling in one direction and the rear of the train may be travelling in the other as the train turns through 180 degrees.  In such instances, there can be a slight tendency for the train to be pulled off the track and this can be exacerbated if the curve is on a gradient.  Long trains, tight curves and steep gradients don't go well together.

 

As you haven't posted a track plan, I can't calculate your maximum gradient, but you will need around 3" minimum between a lower and upper track (ie remember to include for the thickness of your upper track bed as well as the 2 1/2" height of most stock) and therefore to get an average gradient of 1:64, you will require 16' (ie 3" * 64 = 192").  Note that that is an average gradient of 1:64.  If you allow a transition in the vertical plane at the top and the bottom of your incline, then the length of your incline will need to be greater.  Given that you have indicated a baseboard of 8' * 4', I'd be surprised if part of your maximum gradient isn't steeper than you think unless you have a full circuit of the baseboard to go from the lower level to the upper level (ie you are planning some form of inverted figure of eight).  Your calculation may be right, but its definitely worth checking.

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Inclines introduce an additional set of problems when you are designing and operating a layout, and the steeper the inclines or sharper the curves, the more this is so.  These are not insurmountable problems, but you need to be aware of them to prevent them messing up the running on your layout.

 

Firstly, RTR stock runs on fairly rigid chassis, and will not take kindly to sudden dogleg changes in direction, horizontal or vertical. A gentle transition curve is needed to keep the central driving wheels in contact with the track at the bottom of the gradient and to prevent the same central drivers from being a rocking point which will send the leading or trailing wheels skywards at the top.  For this reason it is asking for trouble to have a sharp transition at the top of the gradient with a curve or set of facing points before the wheels land back on the track; the loco will derail.  There may well be implications for smooth power pickup if there are dead frogs in the vicinity as well.  Tension lock couplers should cope, but some other types my not.

 

But, having transition curves in the vertical plane at the top and bottom of your gradient brings another factor into play.  You may have worked out to a degree of accuracy what the steepness of the gradient is, but if you haven't allowed for the vertical transition curves top and bottom it will in practice be much steeper than that in the middle and the haulage capacity of your locos will be affected in consequence.

 

Moreover, a sharp curve on a gradient involves an appreciable degree of twisting of the track, which after 90 degrees will be leaning inwards to the extent of the gradient steepness if you do not twist it back straight.  This may have some effect on some rigid chassis locomotives.  

 

You can easily enough determine what your locos will pull up a given gradient; all you need to do is lay some track on a length of wood and prop it up at one end, and run the loco up it with increasing loads until it slips or stalls.  If it slips, you may be able to get another coach out of it by ballasting over the driving wheels (guess where the least space for ballasting is?) and you might get another one by taking ballast weight out of the coaches, but not to the extent where they do not reliably stay on the track!

 

A bit of prior awareness of the issues and experimentation should get you a workable system, but as Dungrange points out, in practice gradients are nearly always steeper than you intended when you lay them, and set track curves will not help the situation much if you want decent length trains.  Don't forget stuff like the Woodland Scenics polyblocks are designed to work on train sets, i.e. a loco and 2 coaches or 4 wagons on a 6x4 board.  

 

As a rule of thumb, I'd suggest accepting that the steepest parts of your gradient are going to be twice as steep as your arithmetic, which is perfectly correct, has suggested, which is 1 in 32; the ruling gradient on the real S & C is 1 in 100, and that broke many a fireman's heart and back...

Edited by The Johnster
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Prompted by another thread, I just went and had a look at Shinohara's range of Code 100 set track and noticed that they do a much larger range of curvatures than the British manufacturers and their radii seem to be designed to give 2" track centres on curves. Whether this would provide enough clearance for your stock, and where you might obtain the range in the UK, however, I don't know.

 

Scalelink have them on their website. 51mm centres from 22" up to 36". You have to buy a full circle of 12 pieces though.

 

If I ever built my super layout I would consider them as I don't really like flexitrack.

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Scalelink have them on their website. 51mm centres from 22" up to 36". You have to buy a full circle of 12 pieces though.

 

If I ever built my super layout I would consider them as I don't really like flexitrack.

 

Thank you Dave (and Pat).  I am constrained to 4th radius 'cos I can't go above 4ft base depth.  I wonder how the Shinohara product compares with Peco Setrack 4th's ? 

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