Peco Bullhead Points: in the flesh

[34theletterbetweenB&D]

47 minutes ago, Jeff Smith said:

First I must confess to not having any BH points but from what I have seen on this thread I would leave in place the original bonding wires between the stock rails and point rails.  I would cut isolation gaps in the point (closure) rails on the frog side and short the isolated rails to the frog...

Which is all perfectly sensible in principle, but the bonding wires from stock to closure rails are very close to the crossing, so you end up with two short pieces of rail, each in one chair. It's all rather tiresome, could have been much better; but anyone so inclined can put in replacement bonding wires and create and wire up a larger isolated  section as a regular switched live crossing.

 

I find it hard to believe that had Peco  supplied their proven electrofrog arrangement as the only option in their BH range,  that this would have been any obstacle to sales.

[Jeff Smith]

Well you could superglue them in place.....

 

I do agree with your last para.  It would be interesting to learn how many BH users are operating then as Insulfrog?

[Chamby]

22 hours ago, Jeff Smith said:

It would be interesting to learn how many BH users are operating then as Insulfrog?

 

No-one that I know of.  Quite possibly, no-one at all.  People who are in the market for these turnouts are unlikely to be enamoured by dead frogs.  I think this is a classic case of somebody at PECO coming up with a clever concept, then squeezing the tolerances too hard to try and make it workable in practice, then Introducing it on totally the wrong product.

 

The EMGS turnout, using the bullhead rail and produced for them by PECO in electrofrog format, is exactly how the 16.5mm gauge version should have been specified.

[MarkSG]

Even in live frog mode, unifrog points have the advantage over the older style electrofrog in that you don't need insulating rail joiners (unless you have a reversing loop), and all rails are always live. So they're a lot easier to wire up.

 

Mine are currently in dead frog mode, as they're operated by fairly basic solenoids without polarity switches and the control unit that they're currently connected to doesn't have switches either. But the frog power wires are ready to connect when I want to (dangling below the baseboard), and when I replace the temporary DC power system with the DCC one that will run the layout long term, then the frog polarity wires will be connected to the control unit (a DCCconcepts ADS-8sx), thus making the points live frog. And all without having to modify the points in any way.

Edited June 26, 2020 by MarkSG

[John ks]

On 26/06/2020 at 04:26, Jeff Smith said:

It would be interesting to learn how many BH users are operating then as Insulfrog?

A while ago when Peco bullhead was fairly new I built an extension with  about 12 points 

The frog wire was fed through the baseboard & left dangling. If that is what you mean as insulfrog then,

So far so good

John

[Jeff Smith]

Yes, if you have no power going to the frog via a change over switch then it is Insulfrog.

[Chamby]

11 hours ago, MarkSG said:

Mine are currently in dead frog mode....  But the frog power wires are ready to connect.... then the frog polarity wires will be connected to the control unit (a DCCconcepts ADS-8sx), thus making the points live frog. And all without having to modify the points in any way.

 

You have described very well the theory and the marketing concept behind the unifrog.  But as this thread has highlighted, that is not everyone’s experience when they actually do wire up the frog, which it sounds like you have not yet done.

 

Seriously, it will depend upon what you are running through the turnout.  A lot of stuff, it works absolutely fine, as intended, no problem.  However some other stock can encounter the shorting out problems that others have described in this thread.  Your choice is therefore between keeping the dead frog and accepting that some loco’s will need a prod if they stall on the dead bit (mostly likely short wheelbase stuff) OR wiring up the frog to improve electrical continuity - but then some wheels might create a short because of the unifrog design.  So as designed, it’s an ‘either/or’ situation.  If you want both the smooth running provided by electrical continuity and to avoid the shorting out, then that’s where the modifications come in.

 

Of course there is a third option, to leave the point unmodified, wire in the frog,  but don’t run anything that you find shorts out on it....  

 

Nobody’s telling you that you have to modify these turnouts, we’ve just explained how to do it if you find yourself in the same situation as us, and want to do something about it.

[martin_wynne]

A thin smear of epoxy (not paint, it will rub off) on the sides of the rail here:

 

 

is all that is needed to cure the shorting problem. It is caused by the backs of the wheels, so there is no need for anything on top of the rail.

 

It will have minimal effect on the running quality, and easily done after laying, or at any time.

 

Martin.

[tender]

16 minutes ago, martin_wynne said:

A thin smear of epoxy (not paint, it will rub off) on the sides of the rail here:

 

 

is all that is needed to cure the shorting problem. It is caused by the backs of the wheels, so there is no need for anything on top of the rail.

 

It will have minimal effect on the running quality, and easily done after laying, or at any time.

 

Martin.

 

I've yet to lay any of my Bullhead turnouts and feel loathed to start attacking them with a disc cutter to cut the rails. This looks like a good unobtrusive solution. Like Martin says, its easily done after laying if the problem manifests. 

[Harlequin]

1 hour ago, martin_wynne said:

A thin smear of epoxy (not paint, it will rub off) on the sides of the rail here:

 

 

is all that is needed to cure the shorting problem. It is caused by the backs of the wheels, so there is no need for anything on top of the rail.

 

It will have minimal effect on the running quality, and easily done after laying, or at any time.

 

Martin.

 

Yes, exactly.

 

An alternative material would be clear nail varnish: Thin enough to paint precisely, hard wearing, insulating, no need to mix and even comes with it's own brush(!).

 

In fact you could label it, "Miracle Track Short-Stop", and sell it for twice the price!

 

Edited June 27, 2020 by Harlequin

[PMP]

I’ve been using these straight from the pack in DC, set up to test a new layout plan. So far I’ve had no problems With any OO stock shorting out. This includes steam prototype and diesel from Hornby, Heljan, Bachmann, Rapido, from both contemporary releases back to early 90’s. I suspect The problems are more associated with incorrect b2b rather the clearances within the points. The only issue I’ve had is the Hornby 0-4-0 Peckett which at very slow speed will stall due to the short wheelbase.

Edited June 27, 2020 by PMP

[Harlequin]

17 minutes ago, PMP said:

I’ve been using these straight from the pack in DC, set up to test a new layout plan. So far I’ve had no problems With any OO stock shorting out. This includes steam prototype and diesel from Hornby, Heljan, Bachmann, Rapido, from both contemporary releases back to early 90’s. I suspect The problems are more associated with incorrect b2b rather the clearances within the points. The only issue I’ve had is the Hornby 0-4-0 Peckett which at very slow speed will stall due to the short wheelbase.

I note that if you nave not experienced any shorts then you will not have not been able to examine any wheelsets that would produce them...

So what evidence do you have that back to backs are the problem? 

 

I thought it had been established pretty clearly earlier in this thread that the problem is related to axles that crab across the track for various reasons.

[Chamby]

18 minutes ago, PMP said:

I suspect The problems are more associated with incorrect b2b rather the clearances within the points.

 

Hi PMP.

 

Absolutely, checking the back-to-backs is always the first step.  But there are other situations where problems can occur and significantly these are almost always encountered when using the turnouts curved track.  These include:

 

#  double-pivot pony trucks that cause the wheels to ‘crab’ at an angle when traversing curved track, therefore the flanges ride at an angle against the inside of the rail and this widens their profile, reducing the effective back-to-back.  If the bogie ran true then the back to back would be fine, but when running at an angle it is enough to short at the unifrog.  A number of Hornby locomotives feature this pony design, the L1 front bogie being a particularly notorious example.  (There is a locomotive-based solution to this particular characteristic described elsewhere on the forum).

 

#  long rigid wheelbase loco’s where again, the outer wheels track at a slight angle on the curved rail, enough to short out the unifrog - this time due to the length of an inflexible chassis.

 

#  the flangeless trailing bogie wheels favoured by Hornby on many of their 4-6-2 locomotives.  These ‘hang’ over the outside curved rail and can short across the top of the adjacent rails of opposite polarity.

 

#  some RTR stock has wheels fitted with a slightly bulbous back profile, that are proud enough to cause a short.

 

Some of these features give intermittent problems, some can be exacerbated when there is a curved approach to the turnout rather than a straight one, because the curve seems to ‘set up’ the angle of approach to the turnout slightly differently.   It is such a shame that the isolation breaks either side of the frog weren’t placed just a millimetre or two farther away from the nose, it would have avoided all these issues.  That’s essentially what you are doing when modifying the points either electrically, or with epoxy/varnish insulation.

 

It would be easy to moan on about this being a PECO problem, but the reality is that it is nearly always a combination of PECO’s very tight electrical tolerances around the unifrog and the RTR’s manufacturers’ design approach that affects the running characteristics, and the two solutions fall foul of each other when they meet up.

[PMP]

1 hour ago, Harlequin said:

I note that if you nave not experienced any shorts then you will not have not been able to examine any wheelsets that would produce them...

So what evidence do you have that back to backs are the problem? 

 

I thought it had been established pretty clearly earlier in this thread that the problem is related to axles that crab across the track for various reasons.

Well with a wide variety of motive power tools choose from both short and long wheelbase I’ve not (yet) had any shorts. However a friend who has had problems with his, checked b2b’s on that particular loco, a Hornby 31, reset them correctly to 14.5 and the issue disappeared. So there’s ‘some’ evidence. Clearly if my stock doesn’t replicate the fault I can’t investigate it. 
With my stock not doing it, and Peco obviously doing testing before release, I’d suggest there’s evidence that it’s not the track, but rather the equipment used on it that’s the problem. 
 

@Chamby one I’ve not tried is a Britannia, I’ll give that a go later. My points configuration Is shown, two have been altered On the curved section length. Has anyone noted a left or right hand prevalence?

[PMP]

So, bored this evening whilst din dins was on the go, and with unrestricted access to the man cave, I tried one or two items out across a set of three CD75 bullhead turnouts. The configuration is 3 x right hand, one pair set as a crossover. So with one failure due to short wheelbase not bridging the frog, (the Hornby 0-4-0 Peckett), it was time to rummage through the cellar to see what worked. To ensure I got a reasonable sample I made sure that the locomotives ran through all three points in both directions slowly. The the model was turned 180 degrees and then repeated. A couple of these weren’t tested this evening as they have already ‘left the building’. Some of them (57xx’s surprise surprise, and 08’s, DMU’s), are multiples that have worked through this test piece recently whilst checking the viability of the track plan.

So being a positive sort of chap I’ll start with the list of those that worked.

Heljan

CL128 x 2    CL26/27  CL05/07  CL14 CL35 x 3  Falcon  LNER 01

3 x Railcars W&M / Park Royal / AC

Bachmann

FairBurn  57xx 64xx 45xx  101 / 105 / 108 / DLW / MLV / Prot Deltic / LMS Twins

Old CL40  CL 03 / 08/ 24old / 24new / 25 / 37v3 / 47 / 57 / ALCO S2 HO / 1F / 3F Jinty / 3F

Austerity 2-8-0 / 80xxx / 46xxx / 73xxx / 76xxx / 82xxx / C Class / 9F

Hornby

Britannia / Clan (Brit & Clan both pony types tested) Patriot / 61xx / Q / J15 / J50 / 42xx / 2BIL / 2HAL / 08 /K3 / Sentinel 0-4-0 Class 40 CL71 Toby Tram Trainset 0-4-0

Athearn

GP7

Rapido

J70 / GMD-1 HO / SW1200 HO

Dapol

Cl121 / B4 / CL22 / CL52

Lima

Cl31

Vitrains

CL37 / CL47

Proto 2000

SW9 HO

Craftsman

02 Kit Gibson wheels

DJM 14xx

 

Those tried that didn't work

Hornby 0-4-0 Peckett (stalls due short wheelbase)

 

That's around 70 different types from all major manufacturers that work through these points with no shorting or stalling. To me that looks like issues with the points are more likely to be user related, or problems with the equipment such as b2b. Most of these are straight from the box with no rectifications, so there will be some variation in b2b from the manufacturing variations we know we get in RTR. Any that have been rectified for b2b are at 14.5mm, and a few with replacement bogie wheels 42xx, are Gibsons at 14,5mm.

Edited June 28, 2020 by PMP
Add types

[martin_wynne]

1 hour ago, PMP said:

 so there will be some variation in b2b from the manufacturing variations we know we get in RTR. Any that have been rectified for b2b are at 14.5mm, and a few with replacement bogie wheels 42xx, are Gibsons at 14,5mm.

 

It's puzzling that several here have reported setting RTR wheels to 14.5mm back-to-back. I'm wondering where that comes from? The correct back-to-back for RTR 00 wheels (NMRA 110 profile) is 14.4mm, see:

 

 http://www.doubleogauge.com/standards/commercialwheels.htm

 

Setting them to 14.5mm risks bumping against the nose of crossing vees.

 

14.5mm is the old BRMSB standard for the narrower BRMSB wheel profile, e.g. Markits driving wheels.

 

For Gibsons, Ultrascale, etc, the optimum setting is 14.6mm back-to-back.

 

cheers,

 

Martin.

[PMP]

6 minutes ago, martin_wynne said:

 

Setting them to 14.5mm risks bumping against the nose of crossing vees.

 

14.5mm is the old BRMSB standard for the narrower BRMSB wheel profile, e.g. Markits 

cheers,

 

Martin.

Not in my practical experience it doesn’t result in bumping over the vees. Using Peco cd75 nothing less than medium radii on the the few that tight, and large radius for everything else. It also works for the Kato code 83, and micro trains code83 and 70 points I have. 
 

The OO gauge society are irrelevant for my modelling, with no disrespect to the organisation. I suspect the gauge I’m using is BRMSB, it came from Gibson. I’ve been adjusting EM wheels back to OO with it with no problems.

[LBRJ]

 I did not even realise there was still a bit of life in the old DOGA yet - one never stops learning

 I suppose they still have the rubber gauges, guaranteed to fit all eventualities?

 

Sorry for the possibly cynical words, but, when a manufacturer of the worlds most used track in quite a few scales and gauges ( maybe, I dunno really) is suspected of making poor quality goods "cos some people cant make it work" I kinda suspect that it is those "some people" who are doing something wrong.

[martin_wynne]

13 minutes ago, PMP said:

I suspect the gauge I’m using is BRMSB, it came from Gibson. I’ve been adjusting EM wheels back to OO with it with no problems.

 

But EM wheels are a different profile from RTR wheels. The same setting is not used for both profiles. For EMGS profile the optimum back-to-back in 00 is 14.6mm. For RTR profile wheels it is 14.4mm.

 

Martin.

[St Enodoc]

2 hours ago, PMP said:

So, bored this evening whilst din dins was on the go, and with unrestricted access to the man cave, I tried one or two items out across a set of three CD75 bullhead turnouts. The configuration is 3 x right hand, one pair set as a crossover. So with one failure due to short wheelbase not bridging the frog, (the Hornby 0-4-0 Peckett), it was time to rummage through the cellar to see what worked. To ensure I got a reasonable sample I made sure that the locomotives ran through all three points in both directions slowly. The the model was turned 180 degrees and then repeated. A couple of these weren’t tested this evening as they have already ‘left the building’. Some of them (57xx’s surprise surprise, and 08’s, DMU’s), are multiples that have worked through this test piece recently whilst checking the viability of the track plan.

So being a positive sort of chap I’ll start with the list of those that worked.

Heljan

CL128 x 2    CL26/27  CL05/07  CL14 CL35 x 3  Falcon  LNER 01

3 x Railcars W&M / Park Royal / AC

Bachmann

FairBurn  57xx 64xx 45xx  101 / 105 / 108 / DLW / MLV / Prot Deltic / LMS Twins

Old CL40  CL 03 / 08/ 24old / 24new / 25 / 37v3 / 47 / 57 / ALCO S2 HO / 1F / 3F Jinty / 3F

Austerity 2-8-0 / 80xxx / 46xxx / 73xxx / 76xxx / 82xxx / C Class / 9F

Hornby

Britannia / Clan (Brit & Clan both pony types tested) Patriot / 61xx / Q / J15 / J50 / 42xx / 2BIL / 2HAL / 08 /K3 / Sentinel 0-4-0 Class 40

Athearn

GP7

Rapido

J70 / GMD-1 HO / SW1200 HO

Dapol

Cl121 / B4 / CL22 / CL52

Lima

Cl31

Vitrains

CL37 / CL47

Proto 2000

SW9 HO

Craftsman

02 Kit Gibson wheels

DJM 14xx

 

Those tried that didn't work

Hornby 0-4-0 Peckett (stalls due short wheelbase)

 

That's around 70 different types from all major manufacturers that work through these points with no shorting or stalling. To me that looks like issues with the points are more likely to be user related, or problems with the equipment such as b2b. Most of these are straight from the box with no rectifications, so there will be some variation in b2b from the manufacturing variations we know we get in RTR. Any that have been rectified for b2b are at 14.5mm, and a few with replacement bogie wheels 42xx, are Gibsons at 14,5mm.

Your dinner must have taken a long time to cook...

[Jeff Smith]

Sorry, but it seems to me that OO is a minefield.  P4 might have fine tolerances but at least it is consistent....

[St Enodoc]

33 minutes ago, Jeff Smith said:

Sorry, but it seems to me that OO is a minefield.  P4 might have fine tolerances but at least it is consistent....

These arguments have been discussed many times in many places. Let's keep this topic to that of the title.

[Jeff Smith]

Sorry, too many gin and tonics, but the variance within OO standards doesn't help people who think they are buying into an established standard.  I also model in On30/O-16.5 so I do fully appreciate the 'looseness' of OO.

[Andy Reichert]

4 hours ago, martin_wynne said:

 

It's puzzling that several here have reported setting RTR wheels to 14.5mm back-to-back. I'm wondering where that comes from? The correct back-to-back for RTR 00 wheels (NMRA 110 profile) is 14.4mm, see:

 

 http://www.doubleogauge.com/standards/commercialwheels.htm

 

Setting them to 14.5mm risks bumping against the nose of crossing vees.

 

14.5mm is the old BRMSB standard for the narrower BRMSB wheel profile, e.g. Markits driving wheels.

 

For Gibsons, Ultrascale, etc, the optimum setting is 14.6mm back-to-back.

 

cheers,

 

Martin.

 

Just to be consistent in your nomenclature. So 14.4 mm is the DOGS BB "Target" setting. The full tolerance range is 14.4 +/-0.05 mm. Exactly the same dimensioning system as the NMRA Standards use on their website. 

 

Andy

[PMP]

9 hours ago, martin_wynne said:

 

But EM wheels are a different profile from RTR wheels. The same setting is not used for both profiles. For EMGS profile the optimum back-to-back in 00 is 14.6mm. For RTR profile wheels it is 14.4mm.

 

Martin.

Who cares? I don’t.
 

Regardless of how much guff people tell us about that’s not the standard, or what is the standard, the list above tells anyone who has a real practical interest in the product, what works straight out of the tin.

 

Its really not that difficult.