Curved points and derailments

[loco lover]

I am at the start of planning a new layout. My previous layout had a few curved points (insulfrog) and I remember they frequently caused rolling stock to derail when wheels passed through the long gap between the frog and the rail, due to the absence of support to the wheel in question. I remember that this problem did not occur on straight points because they had significantly shorter gaps.
Does anyone know how to prevent this problem occurring?
All replies gratefully received,
Alan

[ITG]

I have a couple of curved insulfrog points, used where space dictates. TBH, although I have had occasional problems in the past (only returned to modelling a couple of years ago, so fairly recent problems), I have now eradicated these, when I moved onto layout 2 (after realising layout 1 was full of beginners mistakes!).

Firstly, I found that if the point isn’t perfectly level, that caused such problems. It did look level to the eye, but after much testing with a spirit level, it wasn’t quite. I used Sundeala board on that layout, and did have problems with sagging and twisting, caused by my poor carpentry on bracing. Secondly, I got rid of older (bought S/H) rolling stock, and/or replaced wheels on some. Older rolling stock also had older style tension lock couplings which may have also been a factor, due to the tighter radii.

 

[Siberian Snooper]

It might help to widen the back to back a little bit and possibly put a shim on the wing rail to tighten up the tolerances, it won't look pretty though. I've not tried it as I build my own track.

 

 

[Chimer]

Were the curved points set-track or streamline?  My last layout had a crossover using streamline curved points which didn't cause me any such problems - and I don't claim to lay perfect track!

[The Cat Called Charlie]

I have built three layouts over the last few years which have made use of Peco's large radius curved points.

 

On the first layout I did have problems, particularly with Hornby stock which does seem to suffer from variable back-to-back measurements.

 

However, the next two layouts were more reliable and I felt this was because I took much more care in making sure the flexible track that led into and out of the point was already curving to the same radius as the curved point itself, so that the train wasn't suddenly jolted into or out of the turn.

 

My current layout has four large radius curved points and I've had absolutely no problems, even the pesky Hornby stock will run over them.

 

Charlie.

[Butler Henderson]

Peco have significantly reduced the size of the frog on the streamline Code 100 curved points compared to what it use to be. See for example  this image on Rails web site

[Dungrange]

1 hour ago, Butler Henderson said:

Peco have significantly reduced the size of the frog on the streamline Code 100 curved points compared to what it use to be. See for example  this image on Rails web site

 

Where is the check rails on that turnout?  Hopefully that's just a drawing and the real turnouts don't look like that.

[Butler Henderson]

Hattons photo then

[Theakerr]

Not necessarily in order of importance and depends very much on the vintage of the points.  a) add a  10 thou shim to the inside of the check rail, b) reduce the 'drop' height in the space between the frog and the point rails using 10 thou plastic sheet, c) ensure the run into the curve is nice and uniform, d) check back to back, e) ensure point is flat,  f) fit quality wheels that run true and g) replace older points with newer ones especially if the are facing.

[RobinofLoxley]

Haven't got time for a full post but I have posted on this before. Refers to Hornby curved points.

[Mike Buckner]

 

[DCB]

Usual problem is lousy wheel profiles and excessive back to back on the wheelsets. I usually go with 14.2mm and a nice sliding fit.   As a check roll the wheelset through the point, It should not be possible for the frog side flange to strike the frog as the check rail will be holding the wheels away from the frog.    My  loft layout hidden siding approach is all Peco cured Electro frog points circa 25 years old and derailments are minimal.  The curved crossover on the visible section causes continual derailments mainly because the track is ballasted and the points can't move sideways with temperature variations so it bends up and goes hump backed.

Ideally a wheelset will roll through the curved route on a point, without  the flange touching the check rail  but most don't because they are not coned, Hornby Dublo driving wheels and plastic wagon and coach wheels,  peco wagon wheels  and some German stuff seems to be coned, 2000s Hornby doesn't seem to be and the narrow treads don't help.