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westport

points/turnouts

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Hi all, new to modelling and doing plenty of research on the net before starting. One subject I cannot seem to get a simple explanation for is the differences between small/medium/large turnouts. Are they just different lengths? ( the straight sections). Will 2 points in s/m/l set end to end still automatically give double track spacing? What about curved points, going from one curve to its parallel track? Any advice appreciated. Many thanks

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Hi all, new to modelling and doing plenty of research on the net before starting. One subject I cannot seem to get a simple explanation for is the differences between small/medium/large turnouts. Are they just different lengths? ( the straight sections). Will 2 points in s/m/l set end to end still automatically give double track spacing? What about curved points, going from one curve to its parallel track? Any advice appreciated. Many thanks

 

Hi Westport

 

There are two popular 00 gauge track systems:

 

  • set track commonly found in train sets and purchasable as add-ons (e.g. Hornby/Peco)
  • and track systems such as Peco streamline code 100 and code 75 (fine scale).

 

 

Peco streamline code 100 is probably the most commonly used system for model layouts. Setrack systems have a wider non-scale double track spacing to facilitate short radius curves on trains sets so that rolling stock ends do not catch or foul. Peco code 100 has a closer more scale like double track spacing and code 100 points match this. The small, medium and large radius points are to do with the radius on the curve on points. Hence the short radius points are short, and long radius are long. The choice of radius depends on many factors such as the space available, preference for more scale like large radius gentle curves (space permitting), and type of railway scene you are modelling. Mainline double track points ideally should be long large radius points but few have the space for this so often medium radius are used as a good compromise, whereas short small radius curves can look ok in sidings, marshalling yards where space on a model railway is tight, or medium radius if you have the space.

 

Watch a real passenger train crossing from one double line to another and you will see the train of coaches gentle snake at shallow angles from one side to the other, where as on a set track model layout with short radius curves the coaches appear to almost separate so acute is the crossing angles. Long large radius points can accommodate higher scale speeds, whereas in real life a train would have to crawl over short radius length points (e.g. in a marshalling yard, freight/power depot). Curved points are also available in both set track geometry format and code 100. Curved points can be a great space saver and facilitate fast train operations due to almost constant curve around a bend changing from one track to another.

 

Peco streamline points come in two variants: Insulfrog and Electrofrog. The former is the simpler to install, the latter needs additional wiring and a polarity switch, but offers smoother running at crawl speeds over the point (i.e. less plastic for the loco wheels to run over). Google has loads of excellent explanations of the pros and cons of each system.

 

Noel

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Hi can I just add that if you can and have the space try to design your layout to use the largest radius point work.

 

In OO a 3ft radius curve is equal to a 3 chain curve or 66 (real) feet and in modelling terms that would still be to small, I am not sure what the minimum radius is on the main Irish railways, but a real 6ft or 2 meter curve in OO is much more desirable in modelling terms if you have the space.

 

This in not mine and I have nothing to do with it but found this on the web:-

 

https://www.thespruce.com/model-train-track-minimum-curve-issues-2382061

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Hi all, new to modelling and doing plenty of research on the net before starting. One subject I cannot seem to get a simple explanation for is the differences between small/medium/large turnouts. Are they just different lengths? ( the straight sections). Will 2 points in s/m/l set end to end still automatically give double track spacing? What about curved points, going from one curve to its parallel track? Any advice appreciated. Many thanks

 

Just to add some points, (no pun intended!)

 

The difference between small, medium and large streamline points are;

 

Small, 185mm long 12 degree crossing angle 610mm radius

Medium 219mm long 12 degree crossing angle 914mm radius

Large 256mm long 12 degree crossing angle 1524 radius

 

The small radius point is good in small layouts but as Noel says its not very prototypical looking. The long points look great but they take up a lot of space.

 

All streamline points automatically give the same double track spacing, its 50mm centre to centre which is a scale 6' apart between sleepers. Set track points give a track spacing of 67mm. This is better for layouts in small spaces with tight radius. At 50mm apart rolling stock will collide in the curves if the radius is too tight.

 

Curved points are the same 12 degree crossing angle and 50mm spacing. But they are only available in one size with an outside radius of 1524mm and inside 762mm.

 

A common misconception with electrofrog points is that people think that they need to be modified to work on DCC and you need to fit an auxiliary switch to switch the polarity. This is not necessary, electrofrog points work straight out of the box, you just need to fit insulated rail joiners on the vee. The point blades switch the polarity.

The only advantage to modifying the point is when you paint and weather the track. It can also prevent short circuits with older rolling stock with big flanges.

 

Hope this answers your questions.

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Watch a real passenger train crossing from one double line to another and you will see the train of coaches gentle snake at shallow angles from one side to the other, where as on a set track model layout with short radius curves the coaches appear to almost separate so acute is the crossing angles. Long large radius points can accommodate higher scale speeds, whereas in real life a train would have to crawl over short radius length points (e.g. in a marshalling yard, freight/power depot). Curved points are also available in both set track geometry format and code 100. Curved points can be a great space saver and facilitate fast train operations due to almost constant curve around a bend changing from one track to another.

 

Just saw Noels comments

 

One point is that in a prototype crossover, there is actually a straight section in the middle, specifically to avoid a sudden reverse curve. Using PECO geometry it isnt possible to easily do this , irrespective of the radius deployed. If you build you down paintwork using a design tool like Templot, you can actually address to a certain degree, that issue

 

the then the great post Noel

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