Wheel back to back measurements

QUOTE (80class @ 30 Mar 2008, 20:38) <{POST_SNAPBACK}>When I completed the track laying on my fiddle yard, I noticed that two of the five locos I was using for testing where shorting my ECoS when travelling over points. Great I thought a problem with the wiring. Thankfully, the wiring appears to be ok. That leaves me to suspect the back to back wheel measurements as being a problem as the other three locos have no problems.

I then bought the C&L back to back gauge for 00:

However, I am not sure how best to use this gauge. I believe the measurement between the wheel backs should be 14mm, is this correct?

Also, is there an easy way to adjust this on locos or does it involve a complete dismantle to prise the wheels further apart?

Sadly I suspect this will be a problem with quite a few of my locos and I guess is an unfortunate side effect of DCC as it comes with the required better sensitivity of boosters that forces you to use best operating practises!

Rob

Hi Rob

No, you cannot fix ONE back to back as some brands of wheels are thicker in flange than others, and this affects it.

NMRA standard is 14.5 which is OK for the last say ten years of production stock and my personal opinion is that the best performance with current H & B loco's is 14.75.

You should also consider adding 10~15 thou of styrene to the inside of the Peco chackrails so they actually check - this will stop the shorts too.

I am NEARLY finished development of a wheel puller that will allow adjustment without stressing the wheel or misaligning it (MOST existing pullers are bad as they don't support the wheel boss properly)

However - No matter what (1) you WILL have to remove the wheels to adjust.... (2) it will be worth doing - especially if you take them out to 14.75! The loco's will run better, pickup power better, track pointwork and enter curves better and seem smoother and surer on the track without the huge slop thats built into them ex factory!

Richard

PS - I make a gauge for 14.75 . Email me off list if interested.

QUOTE (Expat @ 30 Mar 2008, 22:44) <{POST_SNAPBACK}>Hi Richard,

I have the same question relating to N Gauge. I don't know if I have a problem yet but might as well get my locos checked out now. i.e. What is the best b 2 b and do you do the necessary kit?

Regards,

Expat.

Sorrry Trevor, but here I have to say "I don't know" really - I havent followed the evolution of N scale wheel profiles closely enough to give advice confidently.

Apart from saying that the same sort of advice will apply.

I'd take a look at the NMRA standards + any UK based N scale association - its also possible that the 2mm scale association (which does some stunning stuff, has an excellent reputation and very good website) may have both standard and 2mm standards available on their site.

As to the gauges - I don't right now but I can have them made if a proper defined size becomes clear - quite quickly!

Richard

QUOTE (alastairq @ 30 Mar 2008, 23:23) <{POST_SNAPBACK}>regarding the shimming of check rails....this is an old trick, it appears, being re-juvenated...used in the past to improve 'stock- tracking' through old-style Peco points.......

*** Ouch -hit my hot button

Yes Alistair, right on the money....and how sad it is that we STILL have to recommend this - they've had 25 years to stop Ba**sing it up for every modeller who uses their rubbish but they persist in making it wrong!

Actually what I'd rather say is "make your own, its easier than you think.... and you can make half a dozen properly for the same cost as one manky Peco effort!

Richard

QUOTE (Ravenser @ 9 May 2008, 20:03) <{POST_SNAPBACK}>I think you'll find that the NMRA back to back for RP25/110 wheels is 14.4mm , and therefore matches the DOGA Intermediate standard.

The finer wheels Richard is thinking about would be to RP25/88 and are a different matter . The nearest equivalent would be EM profile wheels (eg Gibsons) , which is what is defined by the DOGA Finescale standard, and that has a Back to Back value of 14.8mm

The DOGA Commercial/Intermediate standards have a revision date of 2004 , which is not "a long time ago" , and by definition a track standard and a wheel standard are two halves of a single whole . If you want to use wheels that don't matchwheel standard A, then it is not surprising if they don't then fit Track Standard A perfectly..

14.5mm has nothing to do with either DOGA or the NMRA , bvut is the old BRMSB figure , and I'd certainly not want to puish current RTR wheels out to 14.7mm or 14.8mm or anything between. That is simply going to ensure the check rails completely fail to operate

***Actually Ravenser I'm actively using 14.75~14.85 depending on wheel profile - yes, including gibson, Steam Era models and Markits PLUS current RTR and having superb running through all forms of turnout - My current layout has more than 100 hand built examples and I have also done the same as an experiment with Peco code 75 and current RTR wheels - setting them to never less than 14.75 after packing the check rails with appx 15 thou of styrene....which is what Peco needs for best performance anyway as their check rails are simply useless as "ex factory"

The result is incontrovertably a 100% success...

The penalty if there is one is that I do have to adjust BTB on every wheel set - but then I've always done that anyway as its critical to good running and the Mfrs can't ever be trusted to get it consistently right. Its no harder to adjust to a slightly wider BTB than a narrower one anyway.

As to NMRA being 14.4.... With the current wheels for most US Mfrs actually now consistently somewhat finer than RP-25 and often trending towards the RP25/88 standard (led by market forces demand) the NMRA 14.4 is now looking very tired and far too close together.

I'm not suggesting its for everyone but the higher running reliability and clearly visible improvement in running even on plain track is to me well worth the effort, and adjusting back to backs to optimise running is just good housekeeping.

Richard