Engine stalls on switch

The most common issue results from loss of continuity at the roller pickups.  I suspect the articulated drive train doesn't help matters.  I suffer this problem on my Atlas 7.5 turnouts, with about half my engines stalling when at a crawl.

The only simple fix is to connect the engine to rollers on the tender, if it has them.  The widely spaced pickups usually ensures that at least one roller is serving the purpose.  And with small engines the problem is solved by mating it permanently with a piece of rolling stock with rollers...say, a lighted caboose.

Bruce

What I do not understand is that this engine does not have a problem going through  other switches on my layout.  No problem through crossover mainline switches.  Only this one situation. Maybe the two switches, 042 and 072 together, creates the problem.   The tender does not have a pick up roller.  Would it be much work to add one?  I may have to seek out that solution.  Thanks for your input.  

Where the engine stops, if you carefully, after turning off the power, lay the locomotive to the side, you will note that both the front and back pick-up rollers are on dead spots. One, on the left switch dead spot, the other on the right switch dead spot. 

This Weaver E8 has rollers spaced 14" apart.

Dead spot in these Atlas switches is about 1 3/4"

The two dead spots in the switches are 14" apart.  The E8 will stop.

Had a similar problem, I suggest that you solder an 18 gauge solid wire to the black hot center rail inboard of both switch points where the left hand and right hand switches butt together. This wire, you will have to determine the length, is then wired to the straight and diverging center black rails of both switches, you may have to solder additional 18 gauge wires to these rails, when ready for connection five wires are to be connected together, I used a wire nut. The center black painted hot rails are not continuous in the Gargraves and Ross switches, by soldering these wire leads, they are in effect jumpers for the hot center rails. With back to back switches the length of this non-powered center rail from the end of the switch to the switch points in your configuration is doubled, this may not be an issue on a single switch, this length is halved and the locomotive power rollers centerline distance is such this rail discontinuity is bridged with not loss of continuity.

What is occurring is a momentary loss of continuity(contact) with the center hot rail, remember to remove the black painted finish on the rails before soldering. All the outside rails are common electrically, you can check this with continuity tester. Also after soldering these wire leads to the center rail I would check their continuity after the five wires are connected by the wire nut.

I am building a large layout with Gargrave Phantom tin plate track and use the continuity tester frequently, most times continuity is wanted, but their are track connections were their is to be selective continuity by use of a toggle switch.    

I laid the engine over at the point of stall.  Stall occurred when the front roller fell in the hole and the the other 3 were in contact with the center section.  Note picture 1,2,3 & 4.  I have good continuity with the center section.  Note three pictures with LED light.  I also soldered a lead to the center section and ganged it to the power lead.  Still experiencing a problem.   Thanks to everyone for the suggestions.  It is getting late so I will have to sleep on it and try again tomorrow.  P.S. Do any of you make house calls?

FWIW:  think about replacing those Gargraves switches with Ross ones.

I had similar issues running TMCC and Legacy steam over Gargraves 0-72.  Briefly tried to monkey with it.  No success at all.

Switched over to Ross.  I did NOTHING but install the switches.  All run flawlessly.

I am familiar with Ross and Gargraves manual switches and the disconnect of the center and divergent center rails.  They make for easy block wiring.  Both of these switches came with DZ-1000 switch machines and thus came prewired for continuity.  I am using Tortoise switch machines and had to isolate the divergent sections with insulated track pins as needed.  The only engine that is giving me a problem here is the articulated yellowstone.  It has 4 center rollers within a span of 12 inches.  My SD24 (2 rollers 6.5" span), 0-8-0 (9.5" span and 3 rollers) & my SD45-T (13" span with 4 rollers) all pass through these two switches without a blink.  Hopefully, tomorrow makes for a good resolve.    

I may have to replace it with a Ross switch.  No problem with my other Gargraves switches - the yellowstone runs through just fine.  Thanks for the suggestion.  I am using Ross curved switches and they are definitely smooth.  

Is it possible one of the rollers is making contact with a common(outside) rail somewhere?  I'm not really familiar with how these switches work, but just what occurred to me looking at the pictures.  Perhaps try placing an amp meter in line to your transformer and see if there is a rise in current from a short with the engine in the dead spot.  

This photo appears to support George's hypothesis of the collector roller touching the outside rail. Put a piece of electrical tape on the that rail to test. That is the curved lead, yes?

Ok, 2nd edit. Try the curved lead with tape and then the thru lead with tape. Whichever is the offender may have to be isolated from the common for this engine.

It certainly looks like it would touch one of them when it "drops into the hole".

After my comments last evening and your reply with the lite continuity tester the problem most likely is an instantaneous shorting of  the power roller(center rail) and common outside rails. If possible, I would remove the truck and check the center roller as is hand rolled through the switch, this should indicate the shorting point of contact. 

Very good trouble shooting.  I would also check each of the (4) pick-up roller to assure there is continuity through the engine pick-up system.

I had one roller on a Weaver M1a that had rusted and did not work.

Also check outside rail continuity.  With that many wheels, lost of outside rail track continuity is probably very small, but it would still be on the Trouble shooting list.  

Excellent point Mike, could be a problem in a soldered wire connection of one of these rollers or maybe a bad negative connection to truck frame.  

   Good point.. here's the reverse  thought... Is a driver or outside wheel  touching the black" hot" thingy the roller rides on, Wonder if electrical tape placed along the side(s) of the thingy  would prevent shorting out (if that's the case). 

I want to thank everyone for all the help.  I have not been able to work on it today, but when it is resolved, I will post my success or failure to solve the problem.  This is my first listing with the forum and I am greatly impressed with the community of help it provides.  Thanks to all for taking the time to help problem solve.  One point I failed to mentioned: my yellowstone is a proto-one engine and I do have an issue with the current soundboard.  I have no chuffing sounds when in forward or reverse.  Bell and whistle work fine while moving.  In neutral, I get all photo sounds.  I plan to have the engine convert to DCS soon and my switch problem, as suggested, might be internal and specific to the engine, rollers, etc.  I will have the rollers checked when the DCS conversion is done.  Will keep you posted as to its resolve, when it happens.  Much thanks!    

P.S.  The two common rails between the points and the frog are neutral, not connected to ground.  I have good outside rail continuity.  

Problem solved!!!  Gregg had it right, electrical tape on the side of the "hot black Thingy" insulated the outside driver preventing the short.  It is now running thru the switch perfectly.  

Thanks to everyone for your insight and help. 

Dave

Good news. glad you found it. Was it near where you have the test lead in that photo?

We've had this one before.   

Carl, I think it was the forward most driver on the articulated engine, or one of four drivers on the fireman side, that made a momentary contact with the wide center rail ("Hot Black Thingy") and this caused the short that created the stall.  When I ran it fast, it would blink, but had enough momentum to carry it past the point of contact and thus get through the switch. At a normal slow speed it would shut down at the short.  With the fix. I can now leave the yard at a normal controlled speed.  Gregg mentioned that this problem has been brought up before.  I assume it was with Gargraves switches.  If that is the case, Gargraves should scale back the heft of the "hot black center thingy" to give more clearance for the larger articulated engines.  Again, thanks everyone for the help.  

Dave

Thanks for confirming, Dave. yeah, I was thinking that big engine needs a #5.

Have fun!