PS3 engine stalls on turnouts

That is suppose to do that its called rule 17 lighting and check your tether make sure its plugged in well til it snaps. 

First, Chessie is correct as regards the headlight. Rule 17 lighting is standard on all PS3 steamers.

If the engine is standing still, the headlight is dimmed and the interior cab light is on. When the engine moves, either forward or reverse, the interior cab light goes out. When going forward, the headlight also gets brighter. I don't recall if it gets brighter or stays dim when moving in reverse.

The tender for the RK Imperial model has wipers on the axles to pick up Common from outside rails, which then goes through the drawbar circuit to the engine. Make sure that the wipers are making good contact with the axles. Also, the screw that holds the tender trucks to the chassis may be too heavily blackened and not conducting the Common. You can connect a wire from each wiper to the tender chassis and see if things improve.

I'm out of town and can't look at my 4-8-2, but isn't there a wiper on the trailing truck?  If so, check the wiring to the wiper.  If none, it might need a wire from wiper to frame.

Problem is often  caused by the combination of traction tires and non-derailing insulated outside rails.

Robert,

You should read all of the thread's posts before posting...

Another issue with many PS/3 locomotives is the 2-rail/3-rail capability.  The switch is a weak point and can result in only one side being common in 3-rail mode.  If that happens, insulated rails can stop you on a dime.

I did, Barry.  Did you?  I see no mention whatsoever of the trailing truck on a locomotive.  You only spoke of tender truck wipers. 

I have never seen a 2R-3R switch that was defective, not to say it isn't possible.

First, make sure wheels and pickup rollers are clean. Very dirty wheels will not have continuity.

This can also be a pickup roller issue on center rail.  Maybe a screw for the wire is loose, or one wire may not be in the wire nut securely.

You can test continuity between pickup rollers to make sure it is 0 ohms.  You can also test continuity between wheels to ensure they have good continuity.   G

Robert,

but isn't there a wiper on the trailing truck?

You didn't specify the that you were discussing a trailing truck on the engine.

Regardless, I checked and there is a wiper on the RK Imperial engine's trailing truck. There is no wire from the wirier to the tender chassis, so the same advice holds true as was stated for the tender's trucks.

My friend Barry, you do die hard.  I had assumed that all forumites would know that in my sentence as written above, the term "trailing truck" referred to the first part of the sentence, wherein I speak of looking at the 4-8-2.  I did not say "look at my 4-8-2's tender..." 

For the benefit of readers, I'll recite the issue.  You may recall, Barry, when I first surfaced the grounding issue on PS3 steamers, on my 2-10-0.  I cured it by running a light wire from the tender wiper to the loco frame, and then you, having also experienced the issue by then, found that the wire could be connected from the tender wiper to the tender frame.

The issue may be related to the lack of a direct conducting drawbar  This may be why MTH has started installing axle wipers, which they did not in the past.  Unfortunately, due to using blackened fastenings for tender and loco trucks, MTH ought to add wires from wipers to frames, on loco trailing and possibly leading trucks, as well as tenders.

Robert,

Unfortunately, due to using blackened fastenings for tender and loco trucks, MTH ought to add wires from wipers to frames, on loco trailing and possibly leading trucks, as well as tenders.

Amen!

I have one right here, wanna' see it?   I admit, it's only a sample of one, but it's fresh in my mind.

I have seen this on real trains that are in the freight yard.Train could be waiting for another train to go by.Or its got a cut of cars to pick up or set off.You to need a bright head light when you are going backward.I was suprised to see steam locomotives runing with their headlights off in the daytime.

"Another issue with many PS/3 locomotives is the 2-rail/3-rail capability."

Well, a sample of 1 is not "many" as originally stated.

2R-3R seems to get a bum rap at timea, but all outside wheels are grounded together when in 3R by the switch.  I think some of this has to do more with dirty wheels, small wheel based engines, and defective switches than 2R-3R engines.

Having said that, this is steam and the engine was working until recently.  So dirty wheels, broken wire, are most likely suspects.  Can be either outside wheels or a center rail pickup issue.   G 

It's been a while since I worked thru and solve my problems, but, here's what I recall for what it's worth.

All PS3 steam engines are not created equal.  I have two Premier steam engines with scale wheels.

One only picks up one polarity of power in 2 rail mode from the engine trailing truck.  The other picks up power in 2 rail mode from the engine trailing truck and the tender front truck.

Also I think I remember that the spring laded pin on top of the drawbar has to make contact on one or the other.  Don't remember which because it's been a while.  But I bought a set of wireless tethers and put one on to shorten the gap between engine and tender and started having the problems described above.  The MTH aftermarket three tether set doesn't have that pressure spring loaded pins on the supplied tethers and no provisions for installing same.  I had to reinstall the original tether to get good performance.

And I have to pay increased attention to keeping wheels and wheel wipers clean in 2 rail DCC operation.  In 3 rail DCS operation on our modular club layout these engines are rock solid. 

That is interesting Bill,  Which engine doesn't pickup power from the tender in 2R.  PS-3 use a 6 connector tether and 2 of the leads on that tether are the transfer of AC or DC track input between engine and tether.   G

My Premier UP 3711  Challenger only has wipers on the engine trailing truck.  This is the engine that was giving me problems across turnouts in 2 rail mode even though I have frog juicers.  

My Premier SP Daylight 4449 has wipers on the engine trailing truck and the tender front truck.  No problems in 2 rail mode with it.

Maybe you can tell me.  Is that "rod" on the tender that sticks down to provide mechanical support for the wireless tether in the circuit? If not, why the spring wire tensioner like on 2 rail DC steam engines?  It seemed to help when I put the original longer tether which came from the factory with the tensioner attached.   

That one never was explained well by MTH, it is a ground connection though.  The engine wheels don't provide continuity from the outside rails on the Challenger?  G

Austin Bill, what is the connection between the wiper on the trailing truck and the loco frame?  If there is a place to connect a thin wire from the wiper to the frame, this might be worthwhile.  This will by pass the lug that connects trailer truck to loco, which is a probable source of intermittent contact.  This is what Barry and I did on our Imperial 2-10-0's, using the tender since these don't have trailing trucks. 

For general info, on the Imperial Decapod, the rearmost set of drivers have insulated wheels--there is no contact between left and right wheels.  The front set have traction tires.  If track work isn't perfect in the vicinity of a non-derailing turnout, the loco can sit with right front driver on the insulated section of rail and the left rear driver which is non-conductive.  At that point, ground can only be had through the tender.

First, I want to thank everyone for all of the advice.  Today was the first I have had a chance to get to try any of the fixes.  Is there a particular spot on the chassis that I should try to attach the wire from the wiper?  The chassis appears to be painted or blackened too.  I assume I need to scrape some of the paint off to make a good spot to solder.

Also, I've noticed the loco always stalls when the front roller on the loco hits the plastic part of the MTH turnout.  The rear roller doesn't seem to matter.  This happens no matter which direction the train travels through the turnout.  Is that significant?

That is interesting, MTH must have used the Premier 2R-3R axles on it.  I had to refresh myself for the Steam 2R-3R wiring.

Because a 2R-3R switch would be in the tender and no comparable switch in the engine;  the engine sends the right wheel connection and the center roller connection across the drawbar connections to the tender 2R-3R switch.  The left side wheels are chassis ground and they connect via the chassis and the spring wire on the drawbar.  In the 3R position both sets of tender wheels are outside ground (because the tender switch connects them), but only the right side engine wheels are sent to the tender via a drawbar wire.   The left side outside track signal goes across via the drawbar spring.

In the 2R position the right side wheels become the equivalent of the center rail pickup and the left side wheels remain ground.  

Diesels are easier since all the wheels and board are in the same chassis.  So the 2R-3R switch connects all the outside wheels together when the switch is in the 3R position.  G

Rugsy, don't solder the wire to the loco or tender frame.  Put it under a screw, preferably with a ring terminal.

Looking at the last paragraph of you last post, are you sure that there is conductivity between the front and rear rollers, at all stages of depressing the rollers, and that both are clean.  It could be coincidence, or a cause.

GGG, I assume your first paragraph referred to the Decapod, an R-K Imperial.  I should add that both wheels are insulated from the axle.  It appears there is insulation between the rim and the main wheel disc.  If this is how 2R-3R loco wheels and axles are made, do they have a finger touching the driver(s) rim(s)?

I tried wiring the wiper to one of the chassis screws, but nothing changed.

I noticed earlier that there was not continuity between the front and rear rollers on the PS3, but there was on another PS2 that I checked.  I wondered if that might have something to do with the problem or was just something different in PS3s.  After noticing it was always the front roller that seemed to create the problem, I checked for continuity between the rollers again and still nothing.  Then after RJR's reply, I checked again.  At first there was nothing.  After checking a couple more locations, I checked the rollers a third time and this time I got continuity???????  So, trying not to breathe on the loco too hard, I put it back on the track and it is working fine now, go figure!

In answer to the question above here's what I found.  Somebody please check my results. 

This was done in 2 rail mode only.

UP 3711,  This engine has intermittent continuity problems.

 Engine has one wiper set on trailing truck.  None on tender.  Wipers connect to right wheels only. 

(Note that the long wiper does not provide much tension and is intermittent on my engine.  Must be carefully bent to provide adequate pressure to make good contact.  I intend to improve this wiper somehow)

Tender drawbar pin connects to tender front truck both left wheels and tender rear truck middle three wheels and tender chassis. 

Engine drawbar pin connects to left drivers and left wheels on lead truck.

SP 4449.  This engine runs well with no continuity problems. 

Engine has one wiper set on trailing truck.  Tender has one wiper set on front truck.  Same weak wiper condition but two sets of wipers are a big help.  Wipers on both connect to right wheels only.

Engine tether pin connects to chassis and left drivers and lead truck left wheels. 

So, the spring loaded pin that comes on the stock wireless tether connects the engine and tender chassis and selected left wheels.

This can be a dirty roller, loose pickup screw, or a broken/pinched pickup wire, or wire not full in the wire nut that joins them.  G

Yes, Left wheels are chassis ground.  Right wheels are either chassis ground when switch in 3R or the equivalent of center rail when in 2R.  G 

Have aPS3 SD90, in 3R mode it does not appear that there is continuity between the wheels. Should there be?

There should be a connection in 3-rail mode.

Yes.  It can be hard to measure because it is a friction/spring connection via the wheels.  G

Thank you, will test again.

To amplify on the power pickup problem.  Since the 3711 Challenger has only the engine trailing truck with wipers on two axles/wheelsets for the right rail contact in 2RL mode it will always remain touchy.

Even worse.  The long wiper at best makes intermittent contact with the front axle/wheelset on the truck.  So, when continuity is broken on the front axle the engine only has ONE WHEEL (none on the tender)  to provide right rail power.  

So, even with powered frogs (Frog Juicers) bad things can happen.

MTH fixed this with the SP 4449 by adding power pickup to the tender front truck -- for a total of 4 wheels making contact.  But the long wipers on both the engine and tender trucks have the same problem.  Too week mechanically to ensure continuity even when clean.

The first thing I will do is somehow improve the long wiper contacts on both engines.  Clearly it would also be nice to add right rail power pickup to another set of wheels in the tender for the UP 3711..

(My primary interest is in the 2 rail solution as both engines run very well in 3 rail mode on our 3 rail club layout -- as long as I pay careful attention to the "wireless" tether staying plugged in which has a tendency to work loose over time.  This has been discussed elsewhere.  I like the idea expressed to put a short piece of tight tubing on the tip of the "rod" after seating the connector.)

Just a question I have since I do not have a Challenger or a SP GS-4. "When referring to "wipers", are they AXLE wipers or "back of wheel" wipers? reason I ask is that the back of wheel wipers are a real curse. They wear grooves in the back side of wheel sets, and in spite of lubricating with a conductive lubricant, they squeak. I run MTH two rail engines on my two rail track. My most recent experience with back of wheel wipers is on the GE test Car sold with the GE EVO Hybrid, with the lights. The engine is beautiful and runs well. The car...its a hanger queen on a shelf. In my opinion, the best possible way to eliminate this problem is to insulate the wheels on one side. That eliminates the wipers entirely.

Hudson.  The UP Challenger and SP Daylight engines both have AXLE wipers made of a very thin (too thin IMO) copper alloy looking material.  It is a one piece unit mounted on the truck frame and insulated from the frame and has two wipers.