RE gaugeing wheelsets

[hayfield]

Some time ago when I asked if P4/S4 wheels could be regauged to either EM or 00 the reply was no as they are of different profile.

 

A week or so ago I asked a question about re-wheeling some Midland clearstories which had P4 wheels, and it was suggested that perhapps I could re-gauge them.

 

Which is correct please. Would they be fine for hand built track in EM or are the flanges just too thin. I can see they will be no good for 00 RTR track

 

I think they are Gibsons as they have blackened axles (I have a set of wagon wheels by the same maker in 00 so they are not exotic ones) which are 25.5mm long where as Keen Maygib are 26.5mm long and bare steel.

 

Thanks

[craigwelsh]

The usual thickness of a P4 tyre should mean they will drop into the crossings on your pointwork due to the extra check gauge width. The flanges wouldn't be an issue if you laid 18.2mm gauge track to P4 standards..

[mcowgill]

You could try it but I suspect they will not run reliably. While you can move the wheels in to narrow the gauge I think you will need to set them to a wider back to back gauge than EM as the S4 flangeway is narrower than that for EM, so you will need to make an allowance for that.

 

As the carriages are S4 are they compensated? If so you might get away with it, otherwise I wouldn't bother as you will almost certainly end up in the ballast on anything but the very smallest of track twist/deviation. You will also have problems over points and crossings as the critical dimensions for S4 are much tighter than for EM.

 

I wouldn't bother, if they are Gibson wheels I'd pop in a set of replacement EM axles, job done and they should run fine with almost no work needed.

[Guest jim s-w]

Hi

 

I am in agreement with Craig on this one - its the flangeway gap that is the big give away of EM track over P4 - I have re-uploaded my 'how a vee works topic' which explains what is going on in this area as a wheel passes.

 

See http://www.rmweb.co.uk/community/index.php/topic/79-the-vee-and-how-it-works/

 

HTH

 

Jim

[hayfield]

Thanks everyone, I printed off a P4 template (just before Jim had kindly posted his V photos) and the flange way gaps are much finer than EM gauge.

 

I have just brought some P4 track gauges as I am determined to build a turnout to P4 standards, so I needed some wheels anyway. I guess I will have to let the others go on Ebay.

 

The coaches are fine, I actually fitted 00 wheels as they are to go behind a GEM compound, funny thing was that one coach needed Romford coach wheels as the Keen Maygib were too loose but the other 4 coaches accepted Keem Maygib wheel without any problems

 

In the shop I thought they were compensated, upon getting them home and looking more closely they were not compensated.

 

But the wires were a Heath Robinson method of stopping the wheels falling out. They run fine now, the problem on my workbench is to stop them rolling away.

 

Thanks again to everyone for such a quick responce.

[Il Grifone]

They should work as long as the flangeways do not exceed 1mm (the requirement for wheels to not drop into the gap is that the wheel thickness has to greater than twice the flangeway - actually a tad more, but large radii mean this is negligible). It's fairly easy to regauge a vehicle to try anyway and then to reset them if necessary. The back to back will need to greater than the usual 14.5/16.5mm for 00/EM due to the thin flanges. Compensation should not be necessary for short wagons and coach bogies, though compensation of bogie vehicles improves their operation. Allow one bogie to only rock fore and aft and give the other free movement to rock sideways as well.

[Guest jim s-w]

Of course if you ensure your EM flangeways are tight enough for a P4 wheel to work then normal EM wheels wont. In the overall scheme of things its not a big deal to get new wheels. Standards are layed down for a reason, they are not just plucked form thin air!

 

HTH

 

Jim

[hayfield]

Jim

 

Thanks, its just when I have something that is quite serviceable I hate getting rid of it. I will keep a set or two of the coach wheels and a set of wagon wheels as I intend at having a go at making a P4 turnout.

 

OK £1.20 is not bad value for a set of wheels but its just a shame I cannot use them. Still they will do someone else a good turn.

[craigwelsh]

They should work as long as the flangeways do not exceed 1mm (the requirement for wheels to not drop into the gap is that the wheel thickness has to greater than twice the flangeway - actually a tad more, but large radii mean this is negligible). It's fairly easy to regauge a vehicle to try anyway and then to reset them if necessary. The back to back will need to greater than the usual 14.5/16.5mm for 00/EM due to the thin flanges. Compensation should not be necessary for short wagons and coach bogies, though compensation of bogie vehicles improves their operation. Allow one bogie to only rock fore and aft and give the other free movement to rock sideways as well.

As you say the wheel thickness must be over twice the flangeway plus the difference between the theoretical crossing nose and the actual blunt nose (something Marin corrected me on in the past as I forgot this). Exactoscale wheels though as an example are 1.71mm wide so wont work so you'd have to check with calipers.. Gibsons are quite wide at just over 2mm but you'll get no checking of the wheels on EM flangeways.

 

Much safer to stick to using the full set of standards or EMF wheels on P4 track perhaps ..

[Il Grifone]

As you say the wheel thickness must be over twice the flangeway plus the difference between the theoretical crossing nose and the actual blunt nose (something Marin corrected me on in the past as I forgot this). Exactoscale wheels though as an example are 1.71mm wide so wont work so you'd have to check with calipers.. Gibsons are quite wide at just over 2mm but you'll get no checking of the wheels on EM flangeways.

 

Much safer to stick to using the full set of standards or EMF wheels on P4 track perhaps ..

 

Undoubtly true, but, if you already have the wheels, it's worth a try. The few I have seem to work OK.

 

I understood the P4 specification for wheel thickness was 2mm. (overscale - the prototype thickness is 5" - presumably to aid smooth running).

[craigwelsh]

Undoubtly true, but, if you already have the wheels, it's worth a try. The few I have seem to work OK.

 

I understood the P4 specification for wheel thickness was 2mm. (overscale - the prototype thickness is 5" - presumably to aid smooth running).

2mm is the max, 1.85mm being the min, see http://www.scalefour.org/history/p4manual.html . Yes, Exactoscale wheels are technically too narrow for P4 and really more suitable for S4 only.. some other wheels are like this too hence why I wanred against assuming 2mm which even then is a bit narrow for 1mm flangeways.