Hornby Locos short my layout

[meatloaf]

This is an odd one...

 

Currently have a Bachmann 20, 24, and 25 and a Heljan 128 and a Dapol 122. All apart from the 24 and 128 have sound. all run great overall my layout and sound works fab. I use peco streamline code 100 points and also have a code 100 double slip. No running issues at all and i use Hornby point clips to make the whole layout live.

 

Now the issue...

 

Every Hornby TTS loco i have tried shorts the layout when it hits the part of the point with the point clip. I have tried the class 20 ( excellent model ) and several class 47s both the RFd version and the large logo blue one. All results in the same thing SVDA on the handset and all the layout goes dead until the loco is moved. When I removed the clips the locos run fine.

 

I think its because the Hornby locos have traction tyres and its the tyre snagging on the clip as they don't fully sit flush against the rail.

 

Anyone else have this issue?

 

Any solution as id  quite like to keep the 20 and get the new 31.

 

I don't want to swap to electrofrog so that's out but I guess I could add a power feed to the sidings instead of relying on clips.

[HLT 0109]

Not had this problem but I found point clips to be a menace!  I have had them glowing red hot because they were making poor contact.  And, if they come loose or ping out, they can cause shorts where they land unseen.  Needless to say I replaced them years ago with soldered wires in place of them.  This is easy if you can remove the points from the layout - turn them over and solder a short, thin wire between each stock rail and its adjacent switch rail (to the non-moving part of the switch rail)  don't whatever you do solder to the inner sides of the rails!  If you can't remove the points. you should be able to drill a small hole through the baseboard adjacent to the outside of each stock rail and switch rail, allowing you to solder wires to the outer sides of each pair of rails - passing the wires under the baseboard.  This assumes you can still reach the points!  You can then throw away the clips.

 

In my opinion this is worth doing even if the clips are not the cause of the shorting problem.

 

Harold.

[meatloaf]

The points are all ballasted in place but are all reachable. The ones in my fiddle yard arent ballasted so could use those as testers. I have considered removing my points and replacing with new electrofrog points, im guessing this would also solve the problem

[John ks]

If the short happens when the wheels reach the frog the it might be the wheel briding the rails from the frog

 

Peco insulfrog points have the frog rails very close together & it is possible for the wheel to short the frog rails

The frog rails(when clips are fitted) are at opposite phases (DCC for polarity) & a wheel bridging this gap will cause a short

 

The following diagrams might help to explain how a wheel can short at the frog

 

 

I have had this problem with insulfrog points & my solution was to paint the top of the frog rails with clear fingernail polish, the area shown in red is about the minimum area that  needs

to be painted

 

John

 

 

[DCB]

Sounds like John Ks is right, but it is the lousy Hornby tyre profile which is sitting flat across the frog instead of being coned and running on the gauge corner causing the trouble.  New wheels should solve the problem, or don't run Hornby.

Hornby point Clips, Peco Insulfrog points and some Hornby wheels are incompatible.

 

You could (should) use electrofrog points, or wire the insulfrog points like electrofrog with isolators at the end of the short rails leading to the frog and feed the rails beyond separately from the buses, obviously you bin the clips and don't bond the stock rails and either rely on the point blades to switch the polarity of the short frog rails or switch them with a pair of microswitches.

[10000]

I believe Peco state on their website not to use Hornby clips on their points. There must be a reason for that apart from competitor product.

 

As John has said use clear nail polish on the frogs but remember that if you use track rubbers or similar you will need to reapply sooner than just by the wear done by the wheels

[40034_Nick]

Not sure if this is any help but.. I had a Hornby Class 58 R250. Peco track and points, i had the same problem. Turned out the wheels were just to fat. !

Basically bined the loco.. 

[34theletterbetweenB&D]

... I have considered removing my points and replacing with new electrofrog points, I'm guessing this would also solve the problem

 

It would. My own findings when converting to DCC on a layout which still had a few insulfrog points in yard areas was that even wheels with a properly coned tyre could and did cause shorts by the bridging at the crossing so well illustrated in 'John KS' post above. Usually the short was so brief that then system did not trip, but the evidence was there in spark erosion of the railhead after the best part of a year of DCC operation ,and the sparking was clearly visible when operating in the dark. I estimated that a visible spark was produced about 1 in every 200 passes over the crossing, which may not sound much: but from trains of the order of fifty four wheel wagons or a dozen coaches on a layout which was intensively operated, quickly mounts up.

[Dunsignalling]

Not sure if this is any help but.. I had a Hornby Class 58 R250. Peco track and points, i had the same problem. Turned out the wheels were just to fat. !

Basically bined the loco.. 

That's a very old loco. IIRC, the wheel profile on them was a hangover from Tri-ang days and was certainly much coarser than those on modern Hornby locos.

 

The OPs issue is with recent, TTS-fitted Hornby locos whose wheels won't be any thicker than those used by Bachmann and Heljan. 

 

John