Peco Bullhead Points: in the flesh

[dasatcopthorne]

Even more interesting.

 

I've never had a problem but have just tested one of my 31s.

 

I pushed the loco over the crossing, forcing it towards to opposing closure rail. On the straight road, it was completely fine.

 

One the curved road I could make it short at one tiny point but only with the forcing over.

 

Dave.

[Chamby]

 

17 minutes ago, dasatcopthorne said:

Has anyone with shorting locos discovered exactly what two pieces of rail are shorting?

 

Dave

 

Hi Dave, Gilbert,

 

The photo below (of an unmodified turnout) shows exactly where shorts can occur.  Different Loco's or stock seem to short out at different places...  Certainly the first thing to do is check your back-to-backs.  Then look for where the wheels might be being pushed against the nearby rail with the opposite polarity, it could be any one of the three places indicated below, where rails of opposite polarity are close to each other.  Problems mostly occur when stock is taking the curved route.  As mentioned before, loco's with a short double-pivot front pony truck such as Hornby's L1 or P2 are particularly prone, also Hornby Pacifics with the flangeless trailing pony truck wheels that swing out of gauge on curves, and some Loco's with long wheelbases.  For some reason I still haven't fathomed, I have one Bachmann Deltic that does it too, but not others.  

 

The modifications I make are shown on page 46 of this thread.  RFS above has kindly provided a link above.  Essentially, I convert the turnout to an electrofrog format.

The Unifrog can short out in any one of the three places ringed red: usually it is caused by the back face of a wheel flange touching the opposite polarity rail.  Hornby's flangeless training pony wheels on their Pacific locomotives can also swing outwards on the curved rails, bridging the gap and creating a short.  

 

With the unifrog, it is the frog nose, and the two check rails aside of it that change polarity when the frog is thrown.  The modification makes all the adjacent rails the same polarity as the frog, and moves the electrical breaks further away from the frog.

 

[dasatcopthorne]

With all the 'slop' in 00, how about increasing B2Bs on offenders to 14.7?

 

Dave

[Chamby]

20 hours ago, rob D2 said:

I have this issue with all three blue ones,of course they have a lot of slop due to the silly system of collecting current from the axle ends,  my simple low tech solution was to paint on clear varnish either side of the frog by say 5mm, to reduce the chances of the wheels breaching across both rails. It works , at the expense of sometimes the 08 doesn’t like the dead bit .

 

you can see the bits I painted - they are getting a tad mucky 

 

Hi Rob,

 

Yes, using varnish is a 'quick fix' but the problem will return with wear, or it may give rise to stalling problems as you are creating a 'dead section'.  It also won't last long if you use a track cleaning rubber!   

 

The modifications, I agree, are rather more tedious, but they do give you both a permanent resolution and better electrical continuity.

 

Nice ballasting, by the way...

 

 

 

Edited June 21, 2020 by Chamby
clarification

[RFS]

Re-wiring as Chamby has done is quite possible with these turnouts. But it looks as though the forthcoming slips and crossings may have the same problem, and will be nothing like as easy to bodge ....

[Joseph_Pestell]

Perhaps the delay in bringing out the diamond and slips is precisely because they recognise the problem and are seeking a solution. I well recall a friend's layout (N) where he had electrical problems with a diamond. Much more difficult to resolve than for a turnout. He ended up having to use a DPDT switch which was a bit of a pain operationally.

 

Silly thing is that several people here on RMweb told Peco that their arrangement would not work properly. They did not take notice.

[gr.king]

The danger is, that any comment about the faults of the design will simply precipitate another round of bickering on here, but for me they are the wrong compromise in as much as they are a "design not so clever" attempt to pass off what is really (adaptable, admittedly) miniature dead-frog design as something called "unifrog", and the timbering does not achieve proportionality of appearance to the under-scale gauge, within the structure of the point, but instead pays too much attention to nominal 4mm scale spacing and has the timbers most widely spaced around the crossing. But....they are what they are, still a great improvement over the look of traditional, "Euro-generic" HO Streamline.

 

I think users just have to accept the reality of the fact that they are not fully suitable for certain modes of use straight out of the packet. If you want them to be exactly as you prefer, then you have to do something about it before using them.

Edited June 22, 2020 by gr.king
Spelling mistake!

[34theletterbetweenB&D]

The simplest option would be a return to the proven live crossing design. 'Unifrog' is for what? Surely anyone buying these will already be a live crossing convert.

[Free At Last]

It will be a bad move if they ever change the fb Streamline range of turnouts to Unifrog. 
I have put a pre-order in for when stocks resume for the rest of the live frog turnouts I will need, just in case.

[Harlequin]

Unifrogs are supposed to be usable without modification, to have a simpler electrical design that should be easier for people to use and which is more suited to DCC control.

 

It's a good idea in principle. It should fix the confusion around modifying and wiring up Electrofrog turnouts. (It's really bad that the supposedly RTP Electrofrog product usually has to be modified before it can be used. It confuses newcomers no end!)

 

I think Peco can easily fix the Unifrogs - they just need to move the insulating breaks in the closure rails further towards the toes - much like Electrofrogs. So let's not throw the baby out with the bathwater.

 

Edited June 23, 2020 by Harlequin

[MarkSG]

16 minutes ago, Harlequin said:

I think Peco can easily fix the Unifrogs - they just need to move the insulating breaks in the closure rails further towards the toes - much like Electrofrogs. So let's not throw the baby out with the bathwater.

 

I agree; I think the problem is simply that the clearances are a bit too tight for some RTR locos. They'd probably only have to move the insulating gap by a millimetre or so to avoid the problem. That would slightly extend the dead area when used in dead frog mode, but I doubt it would be a serious problem for all but the shortest-wheelbase locos. And it wouldn't be any problem at all when wired for live frog mode. Meanwhile, you've still got the advantage that they can be wired up for live frog use simply by connecting the feed, it isn't necessary to make any other modifications.

 

I do like the unifrog concept, and I'm happy enough with the bullhead points that I've installed. But, like a lot of innovative designs, there are some issues which really only become apparent with actual widespread use rather than in-house testing. If they are planning to use unifrogs on the rest of the Streamline range then that's something that can be addressed before they make that change.

[34theletterbetweenB&D]

1 hour ago, MarkSG said:

... I think the problem is simply that the clearances are a bit too tight for some RTR locos. They'd probably only have to move the insulating gap by a millimetre or so to avoid the problem. That would slightly extend the dead area when used in dead frog mode, but I doubt it would be a serious problem for all but the shortest-wheelbase locos...

The clearances are way too tight in my estimation if this product is aimed at coping with all currently manufactured RTR OO wheelsets.  My estimate is an incremental 9mm to the current 26.5mm dead zone to be absolutely safe = 35.5mm; comprising an extra 3mm dead ahead of the crossing on the closure rails, and an extra 6mm after the crossing.

 

Won't fly will it? No, baby out with bathwater time, revert to well proven live crossing only. It's for Peco to decide what market they are aiming at, but I don't think there's much value in trying to accommodate the Hornby 'Mixed Goods' set locos...

[Gilbert]

40 minutes ago, 34theletterbetweenB&D said:

Won't fly will it? No, baby out with bathwater time, revert to well proven live crossing only. It's for Peco to decide what market they are aiming at, but I don't think there's much value in trying to accommodate the Hornby 'Mixed Goods' set locos...

Frankly most of my locos are fine and I like the simplicity of the Unifrog- I'd expect better of a higher end Hornby Class 31 than the sideplay and ?wide wheels that seem to cause the problem.

[autocoach]

I am not currently using bullhead rail having switched to modeling a US prototype.  But my experience with Code 83 Unifrog turnouts that are not wired suggests that every locomotive whether DC or DCC should be outfitted with a Keep Alive/Stay Alive type of capacitor to ensure reliable operation through the turnout as you cannot rely on the somewhat flimsy stamped points to ensure reliable contact over time. Even Code 83 insulated Electrofrog turnouts with the newer stamped points are suspect and do not operate reliably even when wired.  This includes longer wheelbase diesels. 

[jamespetts]

16 hours ago, autocoach said:

I am not currently using bullhead rail having switched to modeling a US prototype.  But my experience with Code 83 Unifrog turnouts that are not wired suggests that every locomotive whether DC or DCC should be outfitted with a Keep Alive/Stay Alive type of capacitor to ensure reliable operation through the turnout as you cannot rely on the somewhat flimsy stamped points to ensure reliable contact over time. Even Code 83 insulated Electrofrog turnouts with the newer stamped points are suspect and do not operate reliably even when wired.  This includes longer wheelbase diesels. 

 

One would preferably wire the turnouts so as not to rely on blade contact: the switch rails should be receiving direct power from droppers. This is how I have wired all of my N gauge code 55 Unifrog turnouts in the fiddle yard of my layout.

[The Stationmaster]

We all have different views - I for example much prefer the crossing ( frog in American railwayese) to be live because it has a number of advantages as far as I'm concerned.  Others prefer self-isolating or dead bits through their pointwork.  Peco has to try to satisfy all of us while at the same time keeping a grip on design and production cists and they have come up with unifrog as their answer to the conundrum.   The only real potential trouble spot is the position of the gap in the switch rails and in my view it would benefit from being moved further from the crossing nose - whether or not that will happen is really down to Peco and their tooling options.

 

As far as it suits me I'm more than happy with the running rails coming out of the crossing to be bonded to the crossing so the small insulations immediately beyond teh crossing are unimportant to me (except they need to be be bonded out and the supplied bonds cut).  But once again this is me, this is what I prefer, this is how I need to alter a unifrog point to use it how I want to use it.  Which takes me back to what Peco have provided - a sort of 'point for all seasons' where various of us have to make changes to get exactly what we need.   But looking on the bright side what we do get is fairly good looking point using a decent rail section at a pretty good price and if we can't make them ourselves that is a big bonus for many of us

 

[Harlequin]

1 hour ago, jamespetts said:

 

One would preferably wire the turnouts so as not to rely on blade contact: the switch rails should be receiving direct power from droppers. This is how I have wired all of my N gauge code 55 Unifrog turnouts in the fiddle yard of my layout.

 

Just to clarify: The OO bullhead turnouts do not rely on blade contact, of course. Every part of them is permanently wired and no electrical switching is performed by the turnout itself. It's up to the user to provide an external switch if he wants to power the frog.

 

This may be different to "Unifrog" products in other Codes and Gauges. (And the OO crossings may be different again - when we eventually see them in a few years time...)

 

[martin_wynne]

17 hours ago, autocoach said:

Even Code 83 insulated Electrofrog turnouts with the newer stamped points are suspect and do not operate reliably even when wired.  This includes longer wheelbase diesels. 

 

The Peco 00 bullhead turnouts have solid rail machined points, not stampings. They are permanently electrically bonded to the stock rails.

 

Martin.

[RBAGE]

Just a small point (pun intended).

In the absence of the PECO bullhead, Unifrog diamond (how long must we wait), if you decide to hand make one, with a continuous crossing vee, then use the PECO conductive rail joiners for bullhead, you can spend a great deal of time trying to find where the short is.

[Blandford1969]

I'd just like to see better availability and the crossings coming out. Fingers crossed as production gets going soon.

[tender]

17 hours ago, Blandford1969 said:

I'd just like to see better availability and the crossings coming out. Fingers crossed as production gets going soon.

The current versions are still available although the major retailers seem to be sold out, but there are still smaller suppliers advertising as in stock. I had a few delivered yesterday.

[Harlequin]

2 minutes ago, tender said:

The current versions are still available although the major retailers seem to be sold out, but there are still smaller suppliers advertising as in stock. I had a few delivered yesterday.

Bullhead OO diamond crossings?

 

[tender]

7 minutes ago, Harlequin said:

Bullhead OO diamond crossings?

 

By 'current' i meant the Bullhead long turnouts. Sorry.

[Zunnan]

On ‎23‎/‎06‎/‎2020 at 19:23, autocoach said:

I am not currently using bullhead rail having switched to modeling a US prototype.  But my experience with Code 83 Unifrog turnouts that are not wired suggests that every locomotive whether DC or DCC should be outfitted with a Keep Alive/Stay Alive type of capacitor to ensure reliable operation through the turnout as you cannot rely on the somewhat flimsy stamped points to ensure reliable contact over time. Even Code 83 insulated Electrofrog turnouts with the newer stamped points are suspect and do not operate reliably even when wired.  This includes longer wheelbase diesels. 

 

I concur with this, I started building a US layout at the start of lockdown using points bought literally days before the shops closed. Running through brand new trackwork even with droppers to every section of track, continuity through the switch blades is so erratic that even my larger 6 axle tunnel motors can stall out where there are two points back to back. I had to bond the stock rails to the switch rails to improve matters, and even then I still get the occasional stall on the stamped switch blades. This before ballasting has been applied, so I haven't even managed to get adhesives into the pointwork to really gum things up yet! Even a Scaletrains unit with their on board keep alive was stalling before I bonded the rails!

 

Thankfully the Bullhead points don't suffer the same with their milled switch blades, but the shorting issue is equally as frustrating. To address the shorting I get sporadically enough to be irritating on my little quarry layout with Hornby Sentinels, W4 and B2 Pecketts as well as Hattons AB tanks, I have decided to bond the rails anyway and convert the frogs to the more usual electrofrog format. Which will be interesting considering the track has been laid for more than long enough now...

[Jeff Smith]

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.  This could be done with a short piece of dropper wire on the outside of each rail across the original isolation.  I would try this first (this could be easily done on already laid points).  If there is shorting at the open end of the V I would do the same thing to both rails just like the original electrofrog points.