GRS point

[hornbeam]

Hi, anyone have a 10 foot right hand point surplus to requirements?

[Peaky 556]

I'm having a look today Simon.

[Peaky 556]

Sorry, no, all mine are quite a bit shorter than 103cm.

[Chris_P]

Is there an easy way to be sure which radius is which as measuring is difficult with a tape measure on one's own.  The GRS catalogue shows 8ft,  10ft and 12ft options but doesn't give lengths although assuming the picture of IG1408R is the 10ft as indicated that appears to have 28 sleepers and assuming the points are built with a jig of consistent spacing the 22 sleeper ones I have will be 8ft radius 840mm long so is the 103cm dimension 10 ft and the 12ft even longer?

Most of what I've seen implies that the generally accepted minimum for G3 is 10ft so is there actually much demand for the 8ft ones, of which I have several, and would it be wise to replace these with 10ft or greater for a new line?

[cabbage]

Chris,
It dies rather depend on the type of locomotives and rolling stock that you use and how the chassis are designed. A B0-B0 loco will take a 2.4m curve, a B0-C0 would not unless the centre axle had a large degree of lateral play. I have a 2-D0-2 loco that takes 3m curves with ease but then it was designed to! But I would buy larger radius curved points for a new part of the layout.

Regards

Ralph

[hornbeam]

Thanks for checking Tim.

I'm only after replacing the 8 foot I have as it son the passenger line and when things pass over at speed it looks a bit daft on a tight curve. I have many 8 foot points and all stick passes ok.

[Peaky 556]

Is there an easy way to be sure which radius is which as measuring is difficult with a tape measure on one's own.  The GRS catalogue shows 8ft,  10ft and 12ft options but doesn't give lengths although assuming the picture of IG1408R is the 10ft as indicated that appears to have 28 sleepers and assuming the points are built with a jig of consistent spacing the 22 sleeper ones I have will be 8ft radius 840mm long so is the 103cm dimension 10 ft and the 12ft even longer?

Chris, you're dead right on the uncertainty of which radius point we have.  The ones I could unearth from my workshop have lengths of 77 and 84 cm, so I'm assuming then I have the 8' and 10' radii.  Simon was looking for one of 103 cm length, which sounds more like the 12' version.  I must invest in some radius curves that drop between the rails and tell us unequivocally what we have!

On the subject of what will and won't go around tight curves, my Peak 1-Co bogie would not entertain the small circle of Geoff Nichols' layout at the AGM this year, but I forget what it's radius was.  Anyone know?

Regards, Tim

[blagdon]

Tim, even my L 1 class Manning Wardle couldn't cope with Geoff's street railway curves!  (Thinks, I need a little 0-4-0 shunter; did I here someone was developing a Andrew Barclay ? )

Ian the Gauge '3' Pirate

[Chris_P]

Tim,

I suspect yours are both 8ft radius but that one of them may have had the normal 3 sleeper lead before the blades shortened as pictures https://www.grsuk.com/shop/Trackwork_GRS-64mm-D302000 suggest that the difference in length between an 8ft and a 10ft will be more than 7cm.

Apart from the issue of how a long wheelbase interacts with a sharp curve there is also an issue of buffer locking where from a little experimentation it is clear a pair of 8ft points forming a cross over are prone to this where the stock or loco has much overhang and even more so if the wheels have significant side play within the axleboxes. The limited range of stock I have has some wheel profiles which allow more side play between flange and rail than others thus making buffer locking even more likely.  Prototype minimal curve radii are often quoted as 6 chains except for some sidings and special applications such as tramways and industrial lines so something around an 18ft radius is probably desirable and consistent with the sorts of figures quoted for the smaller model gauges.

Chris