shorting out 12 1/2 degree Atlas crossing

[captwilb]

 I installed a 12 1/2 degree crossing and the first time I ran my E7 over it it shorted.  When I removed it and looked closely the ends of the rails are too close and will always short out.  I covered the ends of the rails with tape and it worked fine. I went to my local hooby shop (Willis Hobbies) and showed the guys there-we opened a number of other Atlas 12 1/2 crossings and they were all the same.  Their reccomendation was to cover the rail ends with nail polish to avoid shorts.  Can someone explain if this is normal with a 12 1/2 degree crossing?  Am I missing something?

[Texas Zepher]

captwilb

Can someone explain if this is normal with a 12 1/2 degree crossing?

In general yes, it is normal for a crossing (any crossing) to have multiple short circuits in it.  Think about it, the two rails are connected across with the two rails of the other track. That is the very definition of a short circuit.   It is only when the vendors add plastic between some of the rails that the shorts go away.  If they isolate the inside track (crossing) causing the short, how then do they get the power to that track for the train running on the second track. Then they have to run the compromise between the short circuits and creating dead sections. The bigger or more numerous the plastic parts the fewer dead spots, the smaller or fewer the plastic parts the easier it is for a locomotive to bridge them and cause a short.  Then finally the more gentle the angle (the 12.5 degree in question) the greater the distance there is where the plastic separated rails have to run close to one another.  Too small a plastic shim and even the width of a metal wheel will bridge it (aka Peco insulfrog turnouts).

 

Think of all the problems model railroaders' and manufacturers' have with a turnout frog.  A normal turnout has one.  Then when one thinks of a crossing as a turnout with 4 frogs (or 12 frogs depending on how you look at it), then one can begin to appreciate the engineering and manufacturing problems they are up against. 

Am I missing something?

I don't think so, unless there was some reason you thought it should be easy?

[retsignalmtr]

No you are not missing anything. The hobby shop guys were right. The two diverging rails are too close together and you get a short when the loco or metal car wheels bridge both rails. Painting them with nail polish eliminates the contact point and will not effect operating locos over it. I have to do this with my peco switches. Nail polish is harder than paint and will last longer. Just be careful cleaning your track with a brightboy in that area (it will remove the nail polish). I use black nail polish. You must be using DCC. It probably wouldn't be noticed if you were running on DC. This is a common problem and when are the manufacturers going to correct it. It's probably cheaper to let the modeler continue to use the nail polish.

[wjstix]

Where did you install the insulated joiners when you put in the crossing??

[Hamltnblue]

You can try a couple of other things.

Assuming the track is HO you can try prying the frog with a screwdriver just a little.  Another thing that might work (did for me) is to use a dremel or file to widen the space where the short occurs slightly. It doesn't take much to make a big difference.

[captwilb]

 I did not put insulated joiners around the crossing.  Why would I?  If I isolated it I would need 4 feeder wires on the crossing tp power it and the problem I have would still exist, right?

[retsignalmtr]

Try the nailpolish trick and let us know. You could use paint but nailpolish is harder.

[captwilb]

I will try the nail polish for sure, that seems the best option.  Still, it seems odd that it is designed that way.  By having the end of the rail just an 1/8" shorter it seems this problem could be eliminated.  Thanks for the heads up and I will let you know how it turns out.

[fwright]

captwilb

I will try the nail polish for sure, that seems the best option.  Still, it seems odd that it is designed that way.  By having the end of the rail just an 1/8" shorter it seems this problem could be eliminated.  Thanks for the heads up and I will let you know how it turns out.

As was pointed out, if you want the simpler wiring of dead frogs - and plenty of model railroaders do - then you have to live with the trade-offs between length of the dead area and possibility of short circuits.  The trade-offs affect both turnouts and crossings, and all the more so when the crossing angles are small and the dead area has to be larger.  The longer the dead area, the more likely stalling will occur (and the more lights will flicker and sound decoders reset).  That 1/8" can be critical for shorter locomotives.  The shorter the dead area, the more likely wheels are to bridge 2 rails at opposite polarity, causing a short circuit.  Wheels that are slightly out of gauge or have wider-than-spec treads (flangeless wheels and drivers are a favorite) are more likely to cause the shorts. 

Atlas crossings and turnouts, and Peco Insulfrogs have had this reported problem on occasion.  It doesn't happen to everybody or with every crossing or turnout, but the chances of occurence are much greater with small frog angles.

Nail polish is the well-known temporary fix.  Grinding away some of the offending rail is a more permanent fix.  And powered frogs do away with the problem all together - at the cost of a polarity contact that must be set correctly.

my thoughts, your choices

Fred W

[Hamltnblue]

Revlon has a pretty pink colored nail polish.  I would avoid the metalic sparlke kind though

[retsignalmtr]

Pink? What a girly man