Angle Of Incidence of Turnouts

[gerryo]

Dues anyone know the angle of incidence of Kato turnouts, both #4 and #6?

[katoftw]

Can you reword the question?  I don't think turnouts have anything to do with refraction or chord lines on aeroplane wings.

 

Dunno if this can help, but at the bottom has examples of turnout usage, shows spacing and configuations:- http://www.katousa.com/track-plans/n-plans.html

Edited June 12, 2015 by katoftw

[cteno4]

Gerryo,

 

If you mean the angle the points come out from the straight its 15 degrees.

 

Jeff

[gerryo]

Katoftw. I don't know what you are talking about, "refraction or chord lines of aeroplane wings". These mean nothing to me . I asked about "angle of incidence". As in he following:

 

"Long wheelbase models running over a #4 turnout have a tendency to derail due to the sharp angle at which the diverging track breaks away from the mainline".

 

This is the angle I am talking about.

 

Jeff. I think the 15 degrees is the amount of a circle taken by the curved track. The 2 turnout sizes must be different, otherwise there would be no need for both of them.

[mrp]

For the R481-15 20-220 #4 turnout, the curved track is 15 degrees of a 481mm radius circle.

For the R718-15 20-202 #6 turnout, the curved track is 15 degrees of a 718mm radius circle.

So I guess the #6 has a shallower (and longer) turn, but ends up at the same 15 degree tangent as the #4.

 

I found this diagram helpful.

 

[velotrain]

This site might be helpful

 

http://www.pcrnmra.org/pcr/clinics/Kolm-TurnoutsWhatYouNeedtoKnow-PCR2008-handout.pdf

[gerryo]

Thanx velotrain, that is exactly what I was looking for.

 

gerryo

[katoftw]

"Long wheelbase models running over a #4 turnout have a tendency to derail due to the sharp angle at which the diverging track breaks away from the mainline".

 

This is the angle I am talking about.

 

Jeff. I think the 15 degrees is the amount of a circle taken by the curved track. The 2 turnout sizes must be different, otherwise there would be no need for both of them.

The angle is not the reason why trains derail on #4 Kato points.  The frog and frog wings design is the problem.

 

The angle you are suggesting you are looking for is "angle of intersection," not "angle of incidence."

 

And of course the 2 turnouts are different.  They both have different radi.

Edited June 13, 2015 by katoftw

[kvp]

When a two axle car can pass a tight curve and S curve, but derails on the same radius turnout, then the reason is usually that the back of the wheels or the flanges get caught on the check or wing rails and this lifts off the wheels from the rails. The same reason can cause a train that can pass a certain curve to get stuck on the same curve if the track has a road suface or a crossing.

[POMU]

Angle of incidence is a measure of deviation of something from "straight on" - no matter what you are measuring.

POMU

[velotrain]

So that term works so long as it isn't a wye or curved turnout.

[katoftw]

Anyway, I don't think the geometry terminology is important to Gerry.  I think he must be having issues with his #4 turnouts.  And a simple google search will yield results as to how to fix.

[POMU]

So that term works so long as it isn't a wye or curved turnout.

If the Wye or turnout has a straight lead in yes - strictly a curve - No

POMU

[velotrain]

> a measure of deviation of something from "straight on"

 

I struggled over the wye, but it seemed to me that there wasn't anything truly "straight on" - other than an imaginary continuation of the straight track leading into the wye.

At the actual point where each half of the wye deviates, there is nothing straight to compare it to.

 

I think this whole conversation is the logical version of rivet counting ;-)

[POMU]

The Wye is a continuation after a straight track is placed before it because of the way it is manufactured and sold by Kato  - thus the angle of incidence will occur after a straight track is placed before it .  Not rivet counting.  Just good geometry and physics.  Has nothing to do with why a train derails through the switch - that is a manufacturing problem.

POMU

[velotrain]

The Wye is a continuation after a straight track is placed before it because of the way it is manufactured and sold by Kato  

 

The way it is manufactured and sold by Kato has absolutely nothing at all to do with this.

 

We were discussing the application of Angle of incidence.

 

> thus the angle of incidence will occur after a straight track is placed before it .

 

What if a curved track is placed before it?

[POMU]

You cannot measure the angle of incidence begining with a curve.  The angle of incidence is the deviation which occurs, as a curve, after the "straight on" object is met with some type of force, producing the curve to produce the angle of incidence.

POMU

[E6系]

Perhaps he means the angle of "incidents" ...

[gerryo]

It doesn't matter to me what the angle is called, but there is an angle and sometimes there is a need for it to be known. There is obviously a difference between the #4 and the #6 otherwise Kato, or any other company, would not produce 2 with the same angle.

 

I now have the info I needed, acquired from the NMRA document, so I'm out of the conversation.

 

gerryo

[kvp]

 

It doesn't matter to me what the angle is called, but there is an angle and sometimes there is a need for it to be known.

In this case the only parameters that are required are the curvature of the turnout and the spacing of the guard/frog rails. The angle everyone is talking about is the angle of the frog, calculatable from the curve radius of the diverging direction. Actually it doesn't matter that much, as the derailments are usually caused by a too narrow curve which can bind some cars or the guard rails being too close to the rails causing either binding or the flanges to ride up on them. The latter is also flange and overall wheel size dependent.

 

ps: This angle was important for railway workers to construct the frogs, but its measurements are calculated by the design engineers from the values above and it's much easier to work with the base values than the derivative ones.

[cteno4]

What he wants is the angle that the point blade makes with the straight track.

 

Jeff

[kvp]

For the straight though blade that should be 0 and for the diverging one also 0 at the tip. The common fix for Kato #4 turnouts seem to be to file small pockets into stock rails the for the tips of the blades to sit into, so the inner edges of the rails became smooth at the stock/blade transition points.

 

ps: Having the diverging route branch off at an angled straight is not really a good idea for models or the prototype either. The prototype handles this by curving away the diverging rail slightly more in the straight position and allowing to curve back to the design curvature of the turnout in the diverging position. Model turnouts usually handle this by having a pice of curved rail on a hinge for the diverging route and a piece of straight rail for the straight route. (good examples for this are the Tomix R140 turnouts) Some cheaper turnouts use two straight blades, which decreases or increases the track gauge along the blade and will have an unhealthy angle which can derail trains with less tolerant wheels or at higher speeds. (a bad example is the small Rokuhan turnout) But imho Kato's #4 does have some curvature on the diverging blade, so the lack of a blade pocket is the main cause for split turnouts and the resulting derailments.

[Mudkip Orange]

You guys are nerds.

[katoftw]

Train nerds