Atlas switches that short out on DCC

[aet]

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I am using Atlas switches and everytime a loco crosses over they stall/short. Is there a way to fix this without a lot of work?

Thanks
DT

[mreagant]

I have used Atlas Customline TOs for the most part and on a couple (out of 50 maybe) the rivet that the frog pivots on loses momentary contact if the loco causes the TO to flex, thus causing a short when it passes over.  The fix is actually quite simple.  A tiny piece of aluminum foil (folded to correct thickness) slid under the pivot bar and the bottom head of the rivet with a very small flat blade screwdriver will provide a conducting shim.  Solved the problem for me and cannot be seen under the ballast.

Disclaimer:  I may have used incorrect terms for the TO parts, but if you use a multi-meter on the continunity setting , it is easy to see if there is a full electrical path on all parts of the TO.  You'll need to check it with and without weight (finger pressure) on the pivot.

Good luck.

[mfm37]

 What Scale?  Checking and setting the wheel guage of my N scale rolling stock cured 99% of my shorting problems.

[mreagant]

mreagant

but if you use a multi-meter on the continunity setting , it is easy to see if there is a full electrical path on all parts of the TO.

I went to the layout this morning to make sure I had given you correct proceedures for the 'conductive foil shim' trick and discovered that a DC engine would still pass through but a decoder equipped one would not.  Did the continunity setting check and there was a clear electrical path at all points.  When I set the meter to AC, I got 15+ volts before the TO, but only 5+ across the TO.  On inspection, I discovered that the shim had worked its way partially out over several years of use.  A little repositioning of the shim solved the problem.

My lesson learned was that with DCC do a voltage check first off when trouble-shooting stuff like this.

[TomDiehl]

aet

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I am using Atlas switches and everytime a loco crosses over they stall/short. Is there a way to fix this without a lot of work?

Thanks
DT

Terminology clarity may be in order here. If your loco is stalling, and your power pack does not give an indication of a short, then power is not making it to the loco because of a dead spot in the track. This is an open, which is the opposite of a short, and requires a different troubleshooting method.

The newest Atlas switches have an all metal frog that is electrically isolated from all other rails. For any short wheelbase loco, this will cause it to stall because the wheelbase of the loco is too short to span the frog and make contact on either side. If this is your problem, you'll need to install the Atlas Snap Relays on each switch that's giving you problems. This will power the metal frog, and switch polarity to match the direction the switch is thrown (provided you wire it correctly).

[jfallon]

 The early Atlas Mk I turnouts have a plastic frog, the diverging tracks are set in the frog VERY close together. The insulated part can be bridged by a metal wheel, causing a short circuit. The best fix is replacing the turnouts with newer ones. The cheating fix is to borrow your wife's/girlfriend's clear nail polish and coat the first 1/8th inch of the rails to insulate them. This layer will wear off over time, so you will have to redo it occasionally.

                                                                           John

[mobilman44]

Hi!

I believe I have your answers..........

I'm building a new HO layout, replacing one built in the early '90s.  This is my first DCC layout, but certainly not my first venture with Atlas components.  Anyway, in building the lower level, I used Atlas code 100 # 6 turnouts.  In testing, locos would occasionally short out when going over two of them, but never on any others.  Well, to make a long story short, I found that my used Atlas turnouts actually represented 3 generations!! 

The first generation (that I have) has the "almost merging" frog rails too close together.  Thus, some locos would bridge the two and a short would be incurred.  It's rather obvious when compared to more recent generations, and I removed them from my stockpile.  Using more recent turnouts, I have never incurred a short.

Oh, to go a step further in my testing, I found that my 10 drivered steamers would tend to derail at one turnout but not others.  I finally figured out that the "movable rails" (forgot the proper term) were loosely rivited and would lean outward with the weight of a loco.  These were my "second" generation Atlas turnouts, and they too are now gone.

By the way, I am still a strong advocate of Atlas track products, for the ones that gave me trouble were made before DCC was a big force, and all had lots of run time on my older layouts.

ENJOY,

Mobilman44