# Loco moves but juders when power off



## Hamish (Apr 3, 2015)

Hi, I hope someone can point a finger at my faults because I am really becoming frustrated. 
I have only recently got into model railways and have posted a few topics, which have all been answered successfully so thanks for that, so here is my latest problem. 
I am finally happy with my track layout so have pinned it down and run drop wires from each section down to a bus main. I am running a Bachmann 31-635 pannier tank loco fitted with a Gaugmaster chip using a Hornby Select controller. I have had the loco for about 3 months, running it occasionally to test the track and today have ran it for longer as I understand it has to be ran in. Now, when running in either forward or reverse and turning the controller power pOFF, the loco juders along in the opposite direction. There is also a part of the track where it does a similar thing, it stops momentarily, then moves in the opposite direction for a very short distance then reverts back to the original direction. I must say I did not have this problem until now and after running the loco for 1/2 hour or so. There are also parts of the circuit where the loco stops, when running slowly, and I have to give it a nudge to get it moving again. Any ideas whats happening.
Also why does the loco stop when going over certain points slowly?
As you can see I have quite a few issues and dont know where else I may get answers.
I hope I have given sufficient information, if not then please ask for more.
Thanks in anticipation.


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## CTValleyRR (Jul 26, 2014)

Hi Hamish,

Once again, the British and Americans are two people separated by a common language! I have no knowledge of the specific systems you're using, but there are some general troubleshooting techniques to look at.

First of all, I assume you only have the one loco. If not, try another and see if it exhibits the same behavior.

Secondly, especially when dealing with newly constructed track, always suspect dirt or construction debris, or both. Give everything, both track and locomotive wheels, a thorough cleaning using a mild solvent like denatured or isopropyl alcohol.

When you say "points", do you mean in the British sense of parts of a turnout? Your turnouts probably have insulated frogs, and the loco does not have enough momentum to coast over them at slow speed. The best fix for this is to add a small capacitor to the decoder to provide a short duration of power over dead spots.

The other issues sound like you have a short, which may be caused by a reversing loop ( a section of track which allows a train to continue forward but end up heading over the same section of track in the opposite direction). These will need to be isolated and controlled through a separate relay. Otherwise, get out the megger and check your track. I would suggest voltage loss as the cause of the slow sections, but since you have a bus and feeders, that's not likely.


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## wvgca (Jan 21, 2013)

you may have more than one type of issue ... in the area where slow movement of the loco will stop may be dirty track, easy fix, or possible out of gauge, especially if the track is pinned or nailed a little too forcibly through the center of the ties in that area ... in the point / frog area it may be insulated frogs and the 0-6-0 doesnt have good power pickup..the gaugemaster chip [mrc over here] may have corrupted cv tables, i had one that would change direction on certain speed steps [mid range], a reset to factory defaults _may_ help? as far as the movement with hitting the pOFF button, i assume you mean the red STOP button on the top left ... that one i have no idea on ...


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## DonR (Oct 18, 2012)

To keep us US folks up on what this is:

Here is the loco

http://www.oliviastrains.com/trains...-pannier-tank-class-6407-in-gwr-green-livery/

If all 6 of those wheels are power pick up it should not have a problem
going thru even a PECO INSULFROG turnout. However, sometimes
the wires from the wheel wipers break off. You might check to see the
condition of those. As noted, dust quickly builds on the track and also
on the loco wheels. They should be cleaned with alcohol on a cotton swab
or cloth. If you have a multimeter, set it to OHMS. Put one probe on
the front LEFT wheel. Touch the other probe to the center then the
rear LEFT WHEELS. You should get a reading each time. Do the same
with the RIGHT WHEELS. If you fail to get a reading that is indicating
there is a problem with the power pickup wiring.

I see that the Hornby DCC controller seems quite straightforward with
no unusual settings. Similar to the Bachmann EZ.
Are you saying that the train continues on after
you push the RED STOP button? Or does it continue when you
turn the speed control to off? Or is it when you disconnect the
house power? 

I can imagine that a heavy duty capacitor in the Hornby power supply
could store sufficient current to run the loco for a short distance if
the speed control was still up and you merely unplugged the power
supply from the wall. (I have a 12 v DC power supply that was part
of a computer game. It powers LED signal lights. When I unplug
it the LEDs continue on for a minute or so.)

A possible reason that the loco has irratic forward and reverse
running could be poor electrical pickup from the track or a loose
track connection that affects the DCC controller.

Let us know the results of your track maintenance and checks
on the loco.

Don


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## Hamish (Apr 3, 2015)

Thanks for the replies.
First can I say I have tried the loco again today and apart from some issues regarding track cleaniing and realigning sections, which has improved the smooth running of the loco, it seems to be running as it should, which is strange, however I am much happier at the moment. 
As regards the multimeter check I set it to 200 ohms and did get readings on each wheel in turn. I don't know what readings I should be getting, if indeed it matters, but most varied. There were a couple which settled on 0.4, another settled around 1.4ish, the other did not settle, just fluctuate, does this indicate anything?
The stop I was referring to was the speed control dial. When this is rotated to stop the loco it was then it juddered along in the opposite direction, as I say this is not happening now for some reason. The problem seamed to occur after I had run the loco continually for around 30 minutes or so.
It is still stopping or at best pausing, depending upon the speed, when going over the turnout. As I have mentioned there are readings from all wheels so it would seam each is picking up current, they are insufrog so could a drop feed be ran from the dead section to the bus main?
Or is there something else I can do?
Much appreciate the help being given, I am learing new things all the time. One thing I did not realise when laying the track was how very important it is get it right, especially a first oval, running a six wheel loco.
As you can tell I am new to this, enjoying it very much when it goes right but it gets very frustrating when it doesn't, it's only thanks to other members who can help that I can continue.
So thanks to all, but would still like to know about multimeter readings and issue with turnouts, or 'points' as I call them.👍


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## DonR (Oct 18, 2012)

The exact value of the ohm meter readings is not important. You
did find that all 6 wheels are picking up power, however. In view
of that it becomes puzzling why it would pause or stop on
a turnout. Even on an insulfrog turnout the some of the wheels
of that loco should be on a 'live' rail at all times. 

You might do a voltage check on the turnout rails where the
loco stops. There may be bad conductivity between the turnout
rails and adjoining track. Or, the turnout points may be losing
power.

To test this:

Set the meter for AC volts, low range, the track should have
somewhere around 14 to 16 volts.

Now check the voltage on the tracks adjacent to the troubled
turnouts. Then do the same with the turnout rails and points.
Flip the turnout and check again. You should have the same
voltage you had measured on the track at all turnout test 
points. (less than a volt or so variations would be meaningless,
likely the difference in probe pressure on the rails). The most
likely place on the turnout would be the points. Depending on
the turnout design, sometimes the points get their power by
pressing against the static rail. Dirt or corrosion could hinder
the power conductivity, or the points could be damaged.

One other thing occurred to me about the loco itself. When
you were testing did you notice if there may be lateral play
in the wheels? This could cause the pickup wipers to lose
contact with the wheels.

Don


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## CTValleyRR (Jul 26, 2014)

I'm glad you got parts of it sorted, anyway. Does the loco now behave normally when run for more than 30 minutes?

I agree with Don that a loco with 6 wheel pickup should be able to negotiate an insulfrog turnout without stalling. Sounds like you do have a connectivity issue there. Perhaps you can isolate it to one side or the other. You could fix this by adding another power drop to the turnout, or by soldering the rail joiners in place to create a solid, conductive joint. Another thing that might help, if you're relying on the joiners to conduct electricity, is to take a small pair of needle nose pliers and squeeze the joiners firmly onto the rails. There also might be glue, ballast, sawdust, foam, corrosion, dust, or something else down inside the joiner which is preventing good contact. Sometimes, this can be fixed by giving it a quick burst of contact cleaner spray or flowing a conductive liquid like Neolube down into the joint.

Also, that lesson you learned about the necessity of bullet-proof trackwork? File it away and never forget it. It's one of the cardinal rules of the hobby.


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## irishthump (Jul 1, 2013)

Hi, Hamish.

I'm also from your side of the pond (Ireland to be exact!) and have some first hand experience of the Hornby Select as I own one myself. 

One important thing about the Select is that it is a VERY basic controller, suitable really only for small layouts or as an entry into DCC. It does not conform to NMRA standards which I'm sure any of the guys here will explain is important to ensure that is works well with other brands of DCC decoders. This could be one reason for your trouble, the Select is somewhat notorious for not playing well with other brands of decoder.

Also, most decoders have a setting which allows the loco to be used on a DC layout. If this feature is enabled then what can happen is that the decoder can interpret the DCC signal as a DC signal and become confused! This commonly occurs after a break in power, like when the loco loses contact running over points. The setting should ideally be disabled but the Select is not capable of doing this.

As for the loco stalling over points; this is a common problem with 6 wheel locos. It helps a lot if the points are lying absolutley flat and you mentioned haveing already pinned down your track. Check to make sure you have'nt driven any pins in too hard which can distort the point slightly.

Someone else also mentioned a capacitor in the loco. These are usually attached across the motor contacts and should be removed before a decoder is installed. Can I ask, did you install the decoder yourself?


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## Cycleops (Dec 6, 2014)

I think you should get it on length of test track and hook up your controller. You will then be able to ascertain whether it's the loco or your layout trackwork that's at fault. Your a Select should be capable of running your loco despite being basic. A six wheel arrangement should run over even insulfrog turnouts without trouble. I sometimes find that points can sometimes become distorted or misaligned during laying with the switch rail not making protracted contact with the stock rail. Worth checking.


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## irishthump (Jul 1, 2013)

Cycleops said:


> I think you should get it on length of test track and hook up your controller. You will then be able to ascertain whether it's the loco or your layout trackwork that's at fault. Your a Select should be capable of running your loco despite being basic. A six wheel arrangement should run over even insulfrog turnouts without trouble. I sometimes find that points can sometimes become distorted or misaligned during laying with the switch rail not making protracted contact with the stock rail. Worth checking.


The problem with the Select is not that it is basic, it's the fact that it isn't NMRA compliant.
It does'nt play well with other makes of decoder and that's well documented. 
I used the Select myself for over a year and found it fine when using Hornby brand decoders (and some other brands).


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## Cycleops (Dec 6, 2014)

I didn't know that the Select had issues when running other decoder makes. Thank you.

Edit: I've just noticed that Hamish has a Gaugemaster decoder in the loco. This is likely made by MRC for them like their Prodigy controllers. They don't have the best name for reliability.


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## irishthump (Jul 1, 2013)

Cycleops said:


> Edit: I've just noticed that Hamish has a Gaugemaster decoder in the loco. This is likely made by MRC for them like their Prodigy controllers. They don't have the best name for reliability.


I'm pretty sure Gaugemaster decoders aren't rebadged MRC. There was alot of discussion (on UK based forums) when they were first released and from what I remember they are actually made by DCC Concepts.

I have a few of them and they are very good. Very smooth running and lots of adjustable functions and features. So maybe that rules out MRC! Gaugemaster might have bee reluctant to use them because of their reputation.....

By the way I also use the Gaugemaster Prodigy 2 controller.


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