How common were/are Y points on the real railway?

[Nick G]

I want to add 2 sidings on my layout, I was just going to put a R/H point in then thought about a Y point. It got me thinking how common were they on the real railway would one be used for sidings?

 

Thanks.

[meil]

Very uncommon in the UK.

[Nick G]

1 minute ago, meil said:

Very uncommon in the UK.

 

I had a feeling that would be the case.

[Rivercider]

I had a quick look through my photos, there are not many, but I found a pair at Crediton.

 

 

 

 

cheers

[Nick G]

1 hour ago, Rivercider said:

I had a quick look through my photos, there are not many, but I found a pair at Crediton.

 

 

 

Interesting, thanks.

[meil]

4 hours ago, Rivercider said:

I had a quick look through my photos, there are not many, but I found a pair at Crediton.

 

 

 

 

cheers

They are almost certainly ordinary turnouts with reverse curvature - not 'Y' turnouts.

[DavidB-AU]

Not common, but if you look at enough prototype track diagrams you'll find enough exceptions to the rule to justify pretty much anything!

[clachnaharry]

9 hours ago, meil said:

They are almost certainly ordinary turnouts with reverse curvature - not 'Y' turnouts.

 

What is the difference between an ordinary turnout with reverse curvature and a "Y" turnout?

[meil]

41 minutes ago, clachnaharry said:

 

What is the difference between an ordinary turnout with reverse curvature and a "Y" turnout?

A true "Y" has unhanded split-deflection switches. A turnout with contraflexture does not.

[Aire Head]

23 minutes ago, meil said:

A true "Y" has unhanded split-deflection switches. A turnout with contraflexture does not.

 

Could we have that in layman's terms please?

[hexagon789]

17 minutes ago, Aire Head said:

 

Could we have that in layman's terms please?

Contraflexture means flexing or bending "contra" or against each other - ie bending in opposite directions.

[Aire Head]

8 minutes ago, hexagon789 said:

Contraflexture means flexing or bending "contra" or against each other - ie bending in opposite directions.

I meant split-deflection switches

[kevinlms]

10 minutes ago, hexagon789 said:

Contraflexture means flexing or bending "contra" or against each other - ie bending in opposite directions.

I think a diagram would be a good idea to explain to us ignorant peasants!

[hexagon789]

6 minutes ago, Aire Head said:

I meant split-deflection switches

Apologies!

 

Wouldn't that be where the split is unequal?

 

Ie you have one direction curving by a certain amount, the other by a different amount?

 

As opposed to either equal amounts or one route being straight and the other curved.

Edited May 30, 2022 by hexagon789

[Izzy]

38 minutes ago, kevinlms said:

I think a diagram would be a good idea to explain to us ignorant peasants!

 

I'm doing some now. Be along shortly.

[IWCR]

For modelling purposes with ready to lay turnouts they effectively are the same,  hence they are common.

Most model turnouts can be tweaked to slightly adjust curves and straights to give variations to dead straight or equal Y.

You will need to selectively cut some of the platic base between timbers to allow defelection.

Dont overdo this and note the meaning of "slight",

 

Pete

[Izzy]

Okay, hope this will help. A quick play with Templot. Others could no doubt do much better and clearer.

 

 

Top, a LH A6 point. An A6 has blades with a deflection of 1:24.  As you will see the blade deflection, as you might expect, is to the left.

 

Next, the same but with curvature to the right of the 'main' road. The blade deflection is still to the left.

 

Bottom, an A6 with equal blade deflection. So the total deflection of that 1:24 is divided being 1:48 each side. 

 

The advantage is a larger radius with both routes. But general opinion seems to be that they only found use in goods yards etc.

 

Bob

Edited May 31, 2022 by Izzy
number figure correction

[Ken.W]

3 hours ago, Izzy said:

 

The advantage is a larger radius with both routes. But general opinion seems to be that they only found use in goods yards etc.

 

Bob

 

Colton Jn, ECML Selby Diversion - 125 either direction

[Nick Holliday]

5 hours ago, Izzy said:

Okay, hope this will help. A quick play with Templot. Others could no doubt do much better and clearer.

 

 

Top, a LH A6 point. An A6 has blades with a deflection of 1:24.  As you will see the blade deflection, as you might expect, is to the left.

 

Next, the same but with curvature to the right of the 'main' road. The blade deflection is still to the left.

 

Bottom, an A6 with equal blade deflection. So the total deflection of that 1:24 is 1:12 each side.

 

The advantage is a larger radius with both routes. But general opinion seems to be that they only found use in goods yards etc.

 

Bob

Sorry.  I am probably being totally thick, but none of that makes any sense.  Like many, I suspect, I still have no idea what blade deflection is, and I certainly could not expect it "to the left".  Your second diagram looks, to me, like the first but distorted to give a curve to the previously straight rail.  Can it still be called an A6 turnout and how do we tell that the blade deflection is still to the left?

If you superimpose the two contra-flexed diagrams, there is little to chose between the two, but as the equal blade(?) version is shorter, I cannot see which has the advantage of a "larger radius".

Looking through several albums, from L&YR to GER and LBSCR for starters, I came across plenty of examples of contra-flexed points, particularly at junctions where the two main lines disappear in different directions; so how are we to tell which is which; and did the real track designers call some of them y-points or what?

 

Edited May 30, 2022 by Nick Holliday

[Peter Kazmierczak]

I'd say that Y-points are much more common nowadays, particularly large radius ones at junctions where the space and geometry allows them.

[Reorte]

15 minutes ago, Nick Holliday said:

Sorry.  I am probably being totally thick, but none of that makes any sense.  Like many, I suspect, I still have no idea what blade deflection is, and I certainly could not expect it "to the left".

You're not the only one!

 

After staring at the templates for a bit I'm thinking that the deflection is the direction that is knocking you off carrying on following the smooth path you were on. In the top two templates the bottom rail is a smooth curve (or straight line), whereas there's an angle in the top rail - the set / bend (the 1:24 describing its angle). In the bottom template there is a set in both rails. So in the middle template there's still a definite "straight on" direction, whereas in the bottom neither can be described as such.

 

Is this about right or am I just adding more confusion?

[Flying Pig]

@Nick G a couple of questions:

 

- are you building your track?

- did you mean a Y point in the strict sense, or just a point with curvature both ways?

Edited May 30, 2022 by Flying Pig

[Nick G]

17 minutes ago, Flying Pig said:

@Nick G a couple of questions:

 

- are you building your track?

- did you mean a Y point in the strict sense, or just a point with curvature both ways?

 

Not building my own no. I just wanted to save a little space by using a Peco O gauge Y point rather than a Peco streamline point which is a bit longer.

[Flying Pig]

6 minutes ago, Nick G said:

 

Not building my own no. I just wanted to save a little space by using a Peco O gauge Y point rather than a Peco streamline point which is a bit longer.

 

In which case the distinction between a Y point and a normal point with contraflexure is probably irelevant and you can go ahead and use one if it makes a sensible formation.

[martin_wynne]

@Nick G

 

Hi Nick,

 

Quote

How common were/are Y points on the real railway?

 

If you mean symmetrical Y-turnouts -- not at all common. Used only in sidings and yards, not running lines (except on some very long modern high-speed junctions). A symmetrical Y-turnout is one which is identical if turned upside down.

 

If you mean turnouts which curve both ways -- very common. For example there is one on the inside of every double-track crossover on curved running lines. "Curving both ways" means taking an ordinary handed turnout and curving it in the opposite direction. Known as "contraflexure" or "negative curving". It can be curved a little bit, or a lot. In Templot you make one simply by setting the main-road radius negative.

 

Such turnouts are not identical if turned upside down, so not produced by the trade -- it would mean making both left-hand and right-hand versions available. The prototype doesn't get much of a look-in for commercial pointwork such as Peco.

 

Here's a diagram which might help:

 

 

 

cheers,

 

Martin.

Edited May 30, 2022 by martin_wynne
typo