Unreliable track

[LucaZone]

Hi,

 

Im terrible with electronics, so decided to go down the DCC route. Its been very straight forward to install on my layout, and I got someone in the know to direct where all the track connections needed to be. I have a multiple unit depot layout with storage roads and maintenance sheds as well as an off scene fiddle yard.

 

However, my trains never run reliably or smoothly. Its not shorting out as ive got route setting to avoid a train touching opposing power supplies. Im forever cleaning the track and even then it never gets to a place where trains run smoothly. I also clean train wheels before running.

 

Ive tried audio cleaning fluids, the classic track rubbers, wetdry paper, and all sorts. The layout is stored vertically in a self contained box. It was bulit with exhibitions in mind.

 

Ive spoken to many people who say they rarely clean the track and even when they do its only for a brief time, and yet they have beautiful fault free running and very low speeds.

 

Whats the trick? What do people do?

 

This is seriously killing my mojo for modelling :(

 

Any help much appreciated.

Edited July 1, 2013 by LucaZone

[Martijn Meerts]

Does it happen everywhere, or just on specific track pieces like turnouts? Also, which brand track are you using?

[LucaZone]

Hiya, thanks for the response.

 

Im using Code 55 N-Gauge track for most of the layout.

 

Poor running is general across the louyout but some points are problematic. Ive tried bending the blades slightly to get more rail in contact as the option of under eath direct wiring is out as ive already fixed in place and ballasted the track.

 

Its been suggested that i give a full inspection of the train bogies as I may not be cleaning them as thoroughly as I thought. Ive got a small loop of kato track to test them out on and ensure smooth running.

[cteno4]

Luca,

 

was it running ok with direct dc and no dcc? did this happen just when you moved to DCC?

 

when you clean do you see junk get on the cleaning rags?

 

how often do you have power feeds in the rails and what gauge wire are the feeds and the trunk line? you can come back and add more feeders but just drilling a small hole next to the outside of the rail and soldering the wire onto the outside of the rail. dig out the ballast a bit and you can even solder to the underside/bottom edge of the rail and hide with a bit of ballast over it.

 

last how long its the track total and what amperage dcc power supply are you using?

 

are all your rail joints soldered? if not they might have gotten a lot of glue infiltration when you did the ballasting. 

 

have you tried using a Bright rubber on the top of the rails? those are those abrasive erasers that some use to clean their tracks. it actually sands the rails (some just use 1200-2400 grit sand paper) though and some think this can lead to micro scratches that attract more dirt (its an endless debate), but might be glue and stuff on top of the rails from ballasting and rubbing with cloth and cleaners wont always take that stuff off.

 

but if it was running fine on DC and then went to hell just with dcc then its something with the dcc, and thats usually not enough power drops and needing larger gauge wires. also should be stranded power wire rather than solid core (dcc signals tend to travel on the surface of the cable not the core so stranded gives more surface area).

 

jeff

[KenS]

From your question, it sounds like you have a working layout, and it's the DCC conversion that's the issue.  But I'm going to recap some of the basics first, because DCC tends to show up problems that aren't as obvious, so first rule out the common problems of dirt and rough track/wheel issues. It sounds like you've already had that advice, but perhaps I'll include something new.

 

Martijn's question is the most important: can you identify problem areas?

 

The second question is, what models do you run: new or old, used or fresh from the box?

 

And the third: does it happen with multiple locomotives, or does an individual one have problems at specific locations.

 

And look at your problem locos on track: if they have older "pizza cutter" wheels (wheels with very large flanges) they probably won't work reliably on code 55 track because the flanges will hit the ties or other detail and lift the conductive wheel off the rail, breaking the electrical contact).  Older trains often need code 80 rail for reliable operation. As I'll note below, this can cause problems with DCC even if it seemed to work okay with DC.

 

Unreliable operation can be bad track, or dirt on the track, which can come from the environment or from dirty wheels or wheels with old "traction tires" (rubber O-rings on some wheels) disintegrating onto the track.  But it can be due to wheels that don't track well (lifting up on one side, for example).  If the loco has pickups on only one truck (wheel assembly) or left on one and right on the other, a bad spot in the track (either poor electricity or a rough spot that keeps the wheel off the track) will be much more obvious than with locos that have pickup on both.

 

If you've nailed down track rather than glued it (something older books tend to suggest) the pressure of the nail through the tie can deform track. Track can also simply get bent before you installed it, or if something heavy were set on it during or after construction.

 

After answering the above questions, here are some things to do:

 

1. Try to identify particular locations where there are problems for multiple locos, or locos that have specific problems.

 

2. Look closely from the side at the track at "bad spots" for irregularities (one rail being raised up or lowered relative to the other for a short distance).

 

3. Check loco trucks for dirty wheels, inability or stiffness in tilting side-to-side (normally one should be flexible while the other is not, but this can vary a lot between designs).

 

4. Check non-powered rolling stock for dirty wheels and clean with the "alcohol-soaked paper towel laid over track" method if needed.

 

5. If you have a multimeter, take the trains off, turn the pack up to full, and measure voltage between the rails at and near your "bad spots" and compare with what a good spot looks like. This isn't the best test, because voltage will look fine at low current through a meter in places where it will be very bad normally, but if you see a problem with this test, you have a very obvious and simple wiring problem to fix.

 

6. Another multimeter test if you don't have a feeder on every bit of sectional track: disconnect the power pack and remove all trains.  Then test resistance on the same rail between the feeder and various parts of the layout.  If you see a large resistance, test across the individual rail joiners between the feeder and problem area (touch each rail a few inches away from the joiner to avoid pressure causing it to change behavior). Any resistances of more than 5 ohms across a rail joiner may indicate a problem, and anything of tens of ohms definitely does. Often you can fix this with new (clean) rail joiners, but consider adding power feeders to problem areas. Everytime I do this test with Unitrack, I throw out a few unijoiners that have gotten dirty or bent.

 

If the track has been cleaned with an abrasive cleaner (like the common "bright-boy" abrasive eraser) it will have surface scratches that make dirt more prone to stick.  I only clean my track with soft cloths (cotton pads or wipes or similar) and a vacuum cleaner to avoid that (the track still gets dirty fast, but it's not safely packed away and it's in a dusty basement).

 

And finally, some "cleaning fluids" will attract dust and dirt and while providing a quick fix will ultimately cause you to do more cleaning.  There are other threads here discussing how to clean track and what to use; look at those (here, here, and here). I use alcohol rather than fancy cleaners.

 

BTW, smooth low-speed running is more about the model than the track.  You need a smooth-working motor and gear-train assembly, as well as reliable electricity to 'creep' along the track.  If the model is older, it may need the wheel assembly cleaned and re-oiled. There are some threads here about cleaning wheels (here, and here). DCC can make a bad model run better (assuming the decoder supports one of the features for improved low-speed operation), but it can't solve all flaws.

 

There are other threads about people with similar problems that may be helpful (search for "cleaning").

 

In DCC, the usual problems are shorts, which it sounds like you've checked for. DCC with multiple trains also magnifies resistance flaws in the track (hence test 6) because more current is flowing through the rail, and so more loss occurs for a given resistance.  Erratic connectivity can be a problem in that it causes the decoder to "reboot" in some cases.  How big a problem this is will depend on the decoder, but it is likely to affect low-speed running since that depends on the decoder maintaining "constant" speed, and if it loses its memory, there's nothing to maintain.

 

The best way to detect erratic track connectivity is with a sound-equipped train.  After I bought my first sound-equipped train (on my old HO layout) I discovered every turnout I had was either shorting or losing power very briefly at the frog. Not enough to stop the train, usually, although it caused intermittent problems. And not enough for a moving train to cause the DCC circuit breaker to trip.  But the loco made its "start up" sounds (running compressor, etc) on every turnout.  It's why I eventually abandoned that layout, as rebuilding it wasn't worth the effort.

 

Unfortunately N-scale sound isn't that common, and I still don't have a sound-equipped train to test with (it's been on my to-do list for two years now).

 

DCC will work very well, and can actually hide some problems (minor dirt that doesn't cut power may simply be ignored with a decoder that adjusts to maintain constant speed). But it will also show up certain kinds of flaws in trackwork and locos very clearly, both heavy dirt and bent track or mistracking wheels.

 

And while adding a feeder to existing track is a pain, it's not impossible. Sand off any paint or "weathering" on the side of the rail with a folded bit of fine sandpaper wrapped around thin styrene (or just folded), drill a hole down through the roadbed and subroadbed, position and clamp the wire to the side of the rail (outside where it won't affect wheels) at both ends with heat-sink clamps (haemostats with curved ends work well for this) to protect adjacent ties from melting, some extra liquid flux on rail and wire isn't a bad idea, although I did it with rosin-core solder just fine) and solder, then after it cools wipe off any leftover flux (alcohol wipe), and paint the exposed wire to match existing rail/scenery.

[Ochanomizu]

Hello Mr LucaZone,

 

Please allow me to make some observation in general running of DCC layout.  Your issue will be the result of: Environment, Track, Wiring, Locomotive.  There is much advice already posted about Track, Wiring and Locomotive.  I wish to make comment about Environment.  Please consider temperature and humidity.  What room is your layout in?  Do you have kotatsu or rice cooker nearby?  Does temperature vary considerably in the room?  It is important to lower humidity and stabilize daily temperature change to eliminate condensation on the track.

 

Next.  Of the current.  DC current is 12v.  But actually never.  This is because running EMU, or loco at realistic speed just require 5-7v.  Power is only required while train is moving.  Stationary train has no power unless you are using constant lighting.  But DCC is different.  It run 14v AC all the time, even when train is stationary or running at realistic speed. 

 

My understanding is that electrical current can promote corrosion.  My advice is to stabilize the environment and reduce humidity.  It is the first step to keeping clean track.  Please keep your layout away from laundry, kitchen and other wet room.  Please do not keep in garage or garden shed.  If you keep in garden shed you must install insulation to walls and ceiling.  Please ensure the room is dusted weekly.

[Martijn Meerts]

Hiya, thanks for the response.

 

Im using Code 55 N-Gauge track for most of the layout.

 

Poor running is general across the louyout but some points are problematic. Ive tried bending the blades slightly to get more rail in contact as the option of under eath direct wiring is out as ive already fixed in place and ballasted the track.

 

Its been suggested that i give a full inspection of the train bogies as I may not be cleaning them as thoroughly as I thought. Ive got a small loop of kato track to test them out on and ensure smooth running.

 

I'm using code 55 Peco myself, and haven't had much issues as of yet, although I don't have a full layout yet :)

 

Turnouts are often an issue, especially the insulfrog versions because they have a rather large bit where a loco won't get any power. For smaller locomotives that usually means it stalls. I've had the same issue on my old layout using Minitrix track, where all turnouts were similar to Peco's insulfrog. I'm using electrofrogs myself, but those pretty much require some modifications for decent operation in DCC, as well as frog polarisation.

 

Another thing to check is the gauge of the wire you're using as feeders. You can have all the feeders you want, but if the wire is of a too small gauge, there will be a lot of power loss, especially on the more distant parts of the layout.

[KenS]

Allan Gartner has a nice page about power loss in wiring (and track, which generally conducts electricity surprisingly poorly). That said, with a standard Kato feeder (which is small gauge) connected to 30' (10m) of track, which is how my current layout was originally wired, while there is a voltage drop of a couple of volts, it's mostly due to the track, and it only mildly affected operation (the train visibly slowed at the far end, but not by a lot. If the wire is only carrying current for one loco, voltage drop in even 30' (10m) of wire isn't going to be more than a volt or two unless you've used really small wire. Where this really matters in DCC is the power bus carrying current for every loco on the layout: that needs to be heavy-gauge wire (there are other threads where we argue about just how heavy).

 

Ochanomizu's comment on humidity is a good one, and I should have thought of that.  I keep a dehumidifier in my basement to try to keep the humidity below 50%, and a did indeed see corrosion on some of the wiring of my old layout in the years before I bought my first dehumidifier, although it was never severe enough to cause a problem.  But others have had problems due to humidity and corrosion.

[Ochanomizu]

Hello Mr LucaZone and Mr KenS,

 

My reply come from comment about "forever cleaning track".  It is the assumption that the track is "forever getting dirty".  Number 1 cause of dirty track is environment.  That is to say, dirty floor (even if your train is on a table), humidity, dust, and temperature fluctuation.  I mention corrosion before, but also, condensation on the track along with electrical current attracts dust and dirt.

 

I think Mr LucaZone must review all propositions on offer.

[Densha]

Concerning dust, this may be a good solution:

 

[LucaZone]

Thank you all for the replies. I am pleased to report that cleaning of trains has been going well, and while the maintenance seems to be small for each unit, they are starting to run much smoother than before. Once I have been through the fleet, I will move onto intense cleaning of the track, and hopefully when the two come back together all will be in a better place.

 

I really like some of the suggestions posted, but for now I have just been focusing on the trains.

 

Thanks again for the help and support shown.

[cteno4]

Luca,

 

great to hear. yeah when dirt builds up enough it starts to get on all the wheels and track pretty well. so first getting all the stock and wheels and pickups clean will get you to a fresh start. then just keeping the track clean usually keeps stuff from building up on the wheels and pickups.

 

good luck, keep us posted.

 

jeff