Locomotives stalling at turnouts

[Anonymous]

I have something odd going on! My layout is primarily a switching layout, based on David Barrow's South Plains District articles. I used Atlas code 100 track and turnouts (all #6's). Four axle diesels, specifically a P2K GP-9, Spectrum GP-30 and Atlas FP-7 balk or stall on almost all the turnouts, but not all the time. Some sort of shorting occurs where the rails come together approaching the frogs of the turnouts. I have tried nail polish, paint, etc. for about 1/8 inch at those points and it helps---sometimes. Now and then the same locos will roll right though the turnout with no hesitation! An Athearn SD-9 (six axles, not four) rolls right through every turnout with no hesitation whatsoever! I am using EasyDCC, mostly Digitrax decoders. I believe the Athearn has a Lenz decoder from three or four years ago in it. Any ideas what I can do to improve the performance of the four axle units through the turnouts?

I have thought of replacing the Atlas turnouts with another brand to see if that helps.

[ndbprr]

I think you can pretty much rule out a turnout problem and concentrate on either the angle of attack for the four wheel truck vs the six wheel or more likely different gauging on the wheel sets or flange depth. Also check tread width on the wheels.

[Anonymous]

Thanks, ndbprr. I would think all the locos involved (i.e. Atlas, P2K, Spectrum) would have RP-25 profile wheels, but maybe not. I'm not sure what you're saying with "angle of attack". Please elaborate because I want to solve this problem.

[ndbprr]

By angle of attack I mean the manor in which the truck passes through the turnout. the closer together the wheels are (four wheel truck) the more play there will be in the way it tracks through the tunrout compared to the longer wheelbase six wheel truck. Kind of like the accuracy differences between a rifle and a pistol due to barrel length. the six wheel truck is going to be more stable in all directions. If the wheel gauge is narrow it is going to compound that problem. Usually close observation while running an engine very slowly over a trouble area several times can indicate exactly where and why the problem is occurring.

[Leon Silverman]

Have you performed a continuity test to see if all of the rails are powered. If the rail between the frog and your insulated rail gap is dead, the longer wheel base on the SD-9 may be able to bridge the gap between the the point end of the switch and the live rail beyond the gap. There may be some oxidation building up inside the frog that prevents the current from crossing the frog when the four axle diesels run through. These diesels are probably lighter than the SD-9, so try adding enough weight to them (at least temporarily) to match the SD-9 and see if the problem persists. If it disappears, put in jumper wires between the point side of the frog and the opposite side.

[Anonymous]

Ndbprr, thanks for the explanation. I see what you mean and I am in the midst of the again and again close observation. Just when I think I have it figured out, it works fine.
To Mr. Silverman: there are no insulated rail gaps. Frogs on these Atlas turnouts are dead, of course, so no current can or should "cross the frog" but since there are no reversing loops and such there is no need for insulated sections, etc. This layout has worked pretty well since 1999, but this problem has gotten worse over time.

[ndbprr]

Worse with time (light bulb going on) Have you cleaned the rails lately? That could be a dirt problem.

[Anonymous]

Yes, clean the rails regularly. Also cleaned wheels on the P2K GP9 earlier this week. Spent some time on the layout last night (Wednesday) and the problem was MUCH better. The only thing that changed was the weather. We've gone from 40 and 50 degree days to 15 degrees yesterday. The basement is heated, of course, but was probably a bit cooler. Could this be related to expansion and contraction of metal (specifically parts of turnouts or even wheelsets)? Last night there were only two troublesome turnouts. Earlier in the week a half dozon or more were trouble spots. I have noticed, and this is probably related to angle of attack, that when one of the 4 axle units stalls in a turnout if I tap the truck that is NOT on the frog it often results in the loco coming back to life. Tapping on the truck on the frog has no effect. Checked wheelset guages with an NMRA guage last night. All are right on. Also checked weight. The P2K GP9 is HEAVIER that the Athearn SD9, but the six wheel truck Athearn rolls through ALL the turnouts with no hesitation whatsoever. Perhaps I should purchase a stable of six axle SDs and retire the four axle units, but that would be a cop out.

This reminds me of a situation in a radio station (used to be in broadcasting) 35 or 40 years ago. We had three Collins cartridge tape players. All the cardtirdges played in two of the machines but some would hang up in the third. Modifying the cartridges themselves helped, but finally figured out, after a year or more of trial and error, that a simple pressure roller adjustment on the one playback unit solved the problem. I WILL solve this turnout issue, but I welcome suggestions and wisdom from all of you. Obviously I'm not smart enough to have resolved this as yet.

Cheers, and Merry Christmas

[Anonymous]

Let me add that ALL the turnouts where problems occur are Atlas code 100. There are four PECO code 100 turnouts on the layout and I don't believe there has been a problem going through any of them. Went though this same thing a couple of years ago and the problem just "went away" one day. Now it's back. I suppose it will just "go away" again eventually, but I'd like to solve the wherefore and why before then so I can prevent it's return.

[rrinker]

Do you have power feeds on both sides of the turnouts? It could also be that the rivets at the pivot point of the point rails has loosened up, causing poor contact in this area.
I started test running over the completed part of my trackwork, and over #4 and #6 Atlas turnouts more than 18 feet from the ONLY feeder I hooked up for temporary power, both a Stewart F7 and a P2K S1 can crawl at tie-counting speed with no hesitation.

--Randy

[Anonymous]

Thanks, Randy. Yes there is power fed from both ends of the turnouts. I think you're onto some about the rivets. In my earlier post about tapping the truck that is not sitting on the frog I realized that the other truck (on a GP-9, for example) is sitting on the points. A little tap there and, more often than not, the loco springs back to life. A less than snug rivet could be affected by expansion and contraction due to temperature changes as well. I have a new avenue of investigation to explore tonight.

[Anonymous]

Interesting... Your PECO switches are not a problem but the others are... hmm.

[rrinker]

QUOTE: Originally posted by ebriley

Thanks, Randy. Yes there is power fed from both ends of the turnouts. I think you're onto some about the rivets. In my earlier post about tapping the truck that is not sitting on the frog I realized that the other truck (on a GP-9, for example) is sitting on the points. A little tap there and, more often than not, the loco springs back to life. A less than snug rivet could be affected by expansion and contraction due to temperature changes as well. I have a new avenue of investigation to explore tonight.

If that's the problem (you can check easily with a small screwdriver - when the loco is stalled, carefully short the point and closure rail together, if the loco starts up, there's the problem.), the fix is easy enough, just solder a short piece of flexible wire from the stock rail to the point and closure rails on the same side. Now the only time it would be a problem is if somehow the rivet worked SO loose that the rail fell off, which isn't too likely.

--Randy

[rrinker]

QUOTE: Originally posted by HighIron2003ar

Interesting... Your PECO switches are not a problem but the others are... hmm.

Hmm, $25 for a Peco, vs $9 for an Atlas plus 50 cents worth of wire and solder (if that), times over 100 turnouts on my final layout plan...

[Anonymous]

Stopped in at LHS today while "making my rounds" (I'm self employed so I can do that!) and looked at a Shinohara turnout. It's not constructed very much differently than the Atlas as far as the points, etc. are concerned. Same rivet situation, etc. WAY MORE price, however. My wife was with me and said, "Let's get your Christmas" so I left with a new P2K locomotive (4 axle). We'll see how it does on the ol' Atlas trainstoppers!

[Anonymous]

Randy,

The screwdriver shorting test provided the answer. You were right. Thanks for your insight!