Peco points. Mixing small/medium/large radius types

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Graeme Leary
GNR C1 4-4-2
Posts: 751
Joined: Fri Oct 28, 2011 9:43 pm

Peco points. Mixing small/medium/large radius types

Post by Graeme Leary »

Huge cringe factor in asking this (as I should know - or logic should tell me) but planning some 'fine tuning' to a part of my layout.

I have the situation where to gain about a foot in length on a passing loop I'm creating (which will also join up with an existing siding - which is, short of major surgery, immoveable as heavily ballasted in place) the best way is to use a 'medium' radius curve point (Peco Streamline) off the main line and a 'short' radius curve Y junction point with one side of the Y (is it the 'toe'?) joining the medium point curve (toe?) and the other toe (?) going into the existing siding. (This condenses the overall length of the 2 points on the loop giving me more 'passing' space - but complicated as Peco do not seem to produce a 'medium' radius Y point and their large radius Y shortens the distance I'm trying to gain on the loop).

However, if I do this will the opposite single track end of the 'Y' 'short' (is it called the 'heel?) still be parallel with the main line that the medium radius has come off or do the different angles of short and medium radius points when joined slightly change the 'parallel' end result of the 2 tracks? (And I don't have a handy model shop to buy 1 of each to experiment with).

Phew - hope you can interpret this - not easy to describe.

Many thanks.

Graeme Leary
drmditch

Re: Peco points. Mixing small/medium/large radius types

Post by drmditch »

Have you considered printing paper templates from the Peco website?
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Atlantic 3279
LNER A4 4-6-2 'Streak'
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Re: Peco points. Mixing small/medium/large radius types

Post by Atlantic 3279 »

The toe is where the blades / switches meet the running rails / stock rails, i.e. the narrow end of a simple point.
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Hatfield Shed
LNER A4 4-6-2 'Streak'
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Joined: Fri Dec 23, 2011 3:34 pm

Re: Peco points. Mixing small/medium/large radius types

Post by Hatfield Shed »

Peco use a constant angle for their streamline points, so (curved points excepted) any two curved roads positioned sequentially opposite handed, deliver parallel tracks.
Graeme Leary
GNR C1 4-4-2
Posts: 751
Joined: Fri Oct 28, 2011 9:43 pm

Re: Peco points. Mixing small/medium/large radius types

Post by Graeme Leary »

Hatfield Shed - thanks for that, sounds as though I can use both the short Y and the medium straight together which will certainly give me that extra length I'm after.

drmditch - thanks also, I did print out the Peco templates but still wasn't sure if would work together. The different 'crossing' angles noted in the Peco catalogue on the 2 types (medium radius 12 degrees and small radius 24 degrees) probably confused me.

Again, thanks.

Graeme
exile
LNER N2 0-6-2T
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Location: France

Re: Peco points. Mixing small/medium/large radius types

Post by exile »

The Y deviates 12 degrees right and 12 degrees left from the straight direction - hence 24 degree angle. Obvious once explained but I can see why it would not necessarily come to mind when looking at the catalogue.
Graeme Leary
GNR C1 4-4-2
Posts: 751
Joined: Fri Oct 28, 2011 9:43 pm

Re: Peco points. Mixing small/medium/large radius types

Post by Graeme Leary »

Exile - now makes sense to a non-mathematical type (and the actual Y and straight points in finished position proves your point). Many thanks.

Graeme
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