# What will happen?



## isoc (Jan 23, 2017)

I am currently DC but thinking of an eventual "transition" to DCC. All (4) of my locomotives are either DCC equipped (with the decoder removed) or DCC ready, with no decoder supplied.

While I think things over and decide what controller to get, and if I want sound or not, I have a question.

I note that, especially (actually exclusively) going through turnouts, that about 20% of the time the light on the locomotive will flicker, about 5% of the time there will be a very slight stutter of the locomotive, but it proceeds normally, and less than 1% of the time it will stall. Track is clean and all that.

If the locomotive had DCC, which, if any, of the above would cause the locomotive to forget what it was doing and want to start over? In DC, even if it stalls completely, a slight touch of the Big Hand and it resumes its activity. If it were a "light flicker" condition like I get about 20% of the time, what happens in DCC? :dunno:

In all the above scenarios, the locomotive is going pretty slow.

Thanks, Ted


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## D&J Railroad (Oct 4, 2013)

I would look at the power connection to the turnout. If it is only track connectors, ya may need to tighten them up or solder them. I would also look at the wheels of the loco. Clean them off with some rubbing alcohol on a paper towel and run the loco over it a few times. If nether of those ideas work, use a hammer.


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## Lemonhawk (Sep 24, 2013)

Well, mostly nothing happens in DCC. If the gap or dead rail is really long then you would have to resort to the HOG. But, the advantage of DCC is that you can install a keep alive in them, either for the Decoder or just the sound part. Then the engine just glides over those dead frogs! Generally you don't need keep alives, but if you run sound it can be annoying to have the sound restart. Since the track is a nice sort of constant A/C the decoders rectify this to DC, where you can stuff in a Capacitor or keep alive. The Decoder just keeps doing the last command it received, so its not bothered by the missing signal.


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## gregc (Apr 25, 2015)

isoc said:


> If the locomotive had DCC, which, if any, of the above would cause the locomotive to forget what it was doing and want to start over?


DCC commands to the locos are constantly repeated. While it may not remember what to do without power, as soon as power is restored it will be told what to do again.


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## flyboy2610 (Jan 20, 2010)

I'm in agreement with Ken. It sounds like inconsistent power at the turnouts. There is a lot of good info on this site: http://www.wiringfordcc.com/


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## DonR (Oct 18, 2012)

I'm always suspicious when there is a report of lights
flickering or loco pauses when going through a turnout.

If the loco has all wheel power pickup there should be
none of those events. First, make sure the loco
wheels and track rails are clean. If not that, there is some problem with the pickup system. You may find the wipers against the back of the wheels are not making good contact, or
you may find a wire from a truck to the motor has come
loose.

If you have a small 4 wheel loco or an older loco that
has power pickup on only one truck you can expect
electrical problems on some turnouts. Wipers can be
added to some of the older loco trucks that don't have
them. Some locos pickup the right rail on one truck
and the left rail on the other. This could result in the
pauses and flickering. You can add wipers to the two
trucks and have all wheel pickup.

There is also the possibility that the point rails are not
making firm contact with the stock rails and thus lose
electrical conductivity. Often careful cleaning can
eliminate that problem.

Don


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## MtRR75 (Nov 27, 2013)

What type of turnouts are you using?

Steam or diesel locos?

These things can make a difference.


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## CTValleyRR (Jul 26, 2014)

While I agree that troubleshooting the source of the turnouts should be on your list of "should do eventually" items, for the immediate answer to your question:

1) A non-sound DCC loco will, in the absence of new instructions, just continue executing the previous one. It wouldn't receive a new command during the power interruption, but, assuming it didn't stall out completely, would continue as before.

2) With sound, as Lemonhawk said, if the interruption is long enough, the decoder might see the restoration of power as the same as receiving power for the first time and go through the startup sequence of sounds again. This would get annoying quickly, I would imagine.


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## isoc (Jan 23, 2017)

MtRR75 said:


> What type of turnouts are you using?
> 
> Steam or diesel locos?
> 
> These things can make a difference.


Turnouts are mostly #5 Walther's 83, but a few Atlas, too.

My S4 and GP7 *never* have a problem, and the rare problems are with a 2-8-0 Bachmann/Spectrum. Don't have my 2-6-0 converted to DCC, so I can't report on it. 

So, although there is some "problem" it is limited to one locomotive, so I'm not too motivated to trouble shoot turnouts. The locomotive wheels are clean, and, as I've said, the "problems" are intermittent, not reliably frequent.

- Ted


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## CTValleyRR (Jul 26, 2014)

I thought you were running DC at this point. 

The one locomotive you have trouble with has limited power pickups, so it's easier to disrupt the current flow. The others have all wheel pickup and don't have the trouble.

Whether it's worth chasing it down or not is up to you.


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## isoc (Jan 23, 2017)

Up until yesterday afternoon at 4:00 pm it was DC. After that it became DCC!


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## flyboy2610 (Jan 20, 2010)

isoc said:


> Up until yesterday afternoon at 4:00 pm it was DC. After that it became DCC!


Welcome to the light side, young padawan. :smilie_daumenpos:


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## ebtnut (Mar 9, 2017)

One other item you need to check is that the turnouts and wheels meet NMRA standards. If you don't have an NMRA standards gauge, get one either from your LHS or direct from the NMRA. Check all of the wheels for correct gauge. If any of them are even a bit wide, they can brush against the open point rail causing a short circuit. In the same vein, if the track gauge is a bit tight and/or the clearance distance between the open point and the stock rail is tight, the same thing happens. If your problem is occuring at only one turnout, then the problem is likely there. If the problem occurs at other turnouts, then the wheel gauge is the likely culprit.


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## isoc (Jan 23, 2017)

Turnouts fit well with the NMRA gauge, and check ok with my voltmeter, too.

The locomotive with the most frequent "stutters" is an S4. Not too bad, and sometimes it goes for 5 minutes or more before it has an "issue," The lights go out when it comes back on, but it usually just keeps going. *Never* have a problem anywhere with a GP7: it has a better "wheelbase" for pickup, I imagine.

And my 2-8-0 is actually OK, it just isn't running as smooth as it did in DC: some occasional "surging" for example, just enough to notice, not enough to not use it. My 2-6-0 is in the shop getting DCC/sound, so it will be a couple weeks before I know how it acts.

Edit : My 0-6-0 was good on everywhere but in a turnout. Since it was to be a yard switcher, that was no good. It had no pickup in the tender , and I didn't want to mess with it so it went back to the hobby shop.
- Ted


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## MtRR75 (Nov 27, 2013)

One other thing to check on your stubborn turnout. At the frog, where the two rails of opposite polarity meet, there is usually a plastic-filled gap between the rails to keep them from shorting. Sometimes steamer drive wheels are thick enough or loose enough (in left-rght movement -- which allows the loco to run on curves) that the driver can make brief contact with BOTH rails at the frog, which leads to a short.

Park the offending loco on the offending turnout. Set the speed on 0, but leave the headlight on. Now, gently wiggle it around to see of the driver might be touching both rails. Watch the headlight for blinking.

If this is the problem, you can use a tiny triangular file (or a Dremel cutting disc if you are brave) to gently file away part of the OUTSIDE of both rails at the frog. This widens the gap between them.


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## Cycleops (Dec 6, 2014)

If your locos are a bit older and sometimes if they're not you might find the flanges are a bit too deep for the turnout frog. It might ride up and loose contact on one side. You can use a sharp tool to dig some material out of the plastic frog.


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