Reply To: Gauge widening on turnouts

Members Forum Track Scratch building track Gauge widening on turnouts Reply To: Gauge widening on turnouts

Paul Willis

@John Cutler said:
Thanks Paul

But I do use the triangular gauges the right way round!
And annoyingly I cannot determine the inconsistency that gives gauge narrowing on the turnouts.
3 out of 9 turnouts recently constructed have given me this issue; the other 6 are fine.

The causes are possibly:
1. Inconsistency in gauge manufacture ( I do have 3 triangular gauges so this is possible).
2. Failure of the triangular gauges to allow for the rail inclination so the rail springs inward from the chairs once the gauge is removed.
3. Lack of matching of the blade planing with the stock rail. I have a feeling that this is at least part of my problem even though I put a set in the stock rail. The new EMGS turnouts have a machined slot in the stock rail into which the planed blade sits comfortably; unfortunately this is probably beyond my skill to reproduce!
4. Poor under-curving of the blades so that they naturally sit under-gauge (again a likely suspect).

My immediate response (=bodge! This is not P4 after all!) has been to move the chairs out a smidgen.
But I wonder if a consistent extra 0.63mm of gauge widening on turnouts would work and if anyone has tried it?
The extra width (0.44mm) of EM tyres over P4 might mean this is feasible.  


Glad to hear that you’re using the gauges the right way around. I have heard of them being used backwards, and by P4 modellers as well ;-)

To your numbered items (I’m not sure that I trust this website to do repeated quoting properly):

1 – either lock two of the gauges in a box and throw away the key… or find a known straight bit of track and try fitting all three on it it turn, in the same place. They should all have a consistent amount of resistance. If not, see which feels best, and put the others in the same box and throw away the key…

2 – definitely a known potential problem. This has been discussed extensively over on the Scalefour Forum. The main solution suggested is to carefully taper out the jaws of the three gripping points so that the rail can “roll” over to the 1:20 inclination when the chairs are glued.

3 – If there is lack of a set in the stock rail, then either make a deeper one (I use a pair of pliers to put the set in rails myself, doing it by eye. There are more sophisticated/consistent ways using a couple of bits of shim and clamping in a vice) or use a needle file to create a notch in the stock rail, as you say the new EMGS points do. Personally, I’d use the first route as it looks more visibly prototypical, but it’s your choice.

4 – This can also be a common problem. Plastic chairs won’t hold a curve in the same way the ply-and-rivet made track will. I’d say that pre-curving until the rail matches the template is an absolute essential if you are going to use plastic chairs for turnouts. I must say that I use a hybrid approach, with rivets to hold everything in line, and plastic chairs for speed and looks.

Good luck!
PS – P4 modellers make just as many bodges as anyone else. We just have an extra 0.63mm to hide them in!