Peco Set Track Curved Points a Warning!

[Tiddles]

Peco do LH ST-245 and a RH ST-244 set track curved points.

But as some point over the years they change the size radius of the points but NOT the part number
The new version is 2nd radius on the inner track and 3rd radius on the outer track. Whereas the older version is 1st radius on the inner track and 2nd radius on the outer track

I discovered this the hard way by buying some used points on eBay that where being advertised as ST-244 and ST-245. Then spent an hour trying to work out why my medium size steam locos would not go around the inner track but are fine on the inner track of the two sets of the newer version that I already had

[Bufferstop]

It's a bit worse even than 1st radius. If you lay a first radius curve over one of the older points you will notice that it's not a uniform curvature. The average between the two ends conforms to 1st radius geometry but at its centre it is actually tighter than 1st. Peco aren't renown for making changes so even they must have thought it unacceptable. I only ever used one once, I very quickly changed the design so that I could use the Streamline curved point.

[Dragonfly]

Ah, I didn't know about the older version of the curved points. Must've been quite a while ago that they made the switch (no pun intended), though, I've never seen the smaller ones (yet).

The new version is 2nd radius on the inner track and 3rd radius on the outer track.

Could I just be picky and point out that actually, the outer curve doesnt equate to 3rd radius, but to a single 2nd radius curve plus a 67mm straight at the point end. That way it lines up perfectly after completing the 90° curves with further 2nd radius points.

[pete12345]

Sounds like they've changed their curved points to match those made by Hornby. They have always been 2nd radius on the inside. The outer curve isn't quite 3rd radius, but 2nd radius with a short straight section. This means that on a 90 degree bend, the outer track will average out at 3rd radius, although you have to use 2nd radius curves to achieve this.

http://www.freetrackplans.com/Geometry.php