vincent marino

How do you explain a dead track area when the voltmeter reads normal?

Mark Gurries

On Jun 23, 2018, at 9:51 PM, vincent marino <vmarino2009@...> wrote:

How do you explain a dead track area when the voltmeter reads normal?
_._,_._,_

You have a open connection.

Voltmeters can lie because they do not require any current to flow of any consequence to measure the voltage.  In other words you can have a very weak electrical connection that cannot support any current and the meter will say everything is OK.

The technical reason is the voltmeter has what is called a very high input impedance.   10 millions of Ohms AKA Megohms or input resistance so to speak.

You can see an example of this if you put the meter in AC mode on the lowest voltage setting and have each one of you hands hold one of the two test leads.  Watch…you have AC voltage!  Play around with this.

You body is acting like an antenna picking up electrical energy in the air.  The meter reads this very weak signal and display a value.

In electronics, one has to know the limitation of the test equipment they use.

Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com

Max Maginness

Is this in a section of plain track, part of a turnout or crossing or has rail joiners at one or both ends?

Seems likely you have a high resistance contact to that section – looks OK on a multimeter voltage range, but drops when any current flow is attempted.

Useful tool  - auto test light  – basically a 12 volt incandescent lamp in a housing with a probe at one end and a clip lead at the other.  Takes enough current to find this sort of  issue.

\

Max

From: w4dccqa@groups.io <w4dccqa@groups.io> On Behalf Of vincent marino
Sent: Saturday, June 23, 2018 9:51 PM
To: w4dccqa@groups.io
Subject: [w4dccqa] Dead track area dcc

How do you explain a dead track area when the voltmeter reads normal?

Gregory Latiak

It is also worth considering the nature of the electrical contact between the pickup(s) and the track in that area. If your rolling stock has a single set of pickups it might be helpful to look very closely at how the wheels track over the area where there is poor conductivity. With my own screwups, mounting a camera at track level and capturing video while the rollingstock traversed the area can sometimes be very educational. And it never hurts to ensure that both the track and the wheels are clean as any crud will magnify other problems.

greg

Don Vollrath

As Mark G says... You have a high resistance connection to that particular section of track.
What does the voltmeter across the track say when a loco is stalled right there? Look for a poor electrical connection at a rail joiner to other powered track or a bropken solder joint in the wiring..

DonV

JerryG

I had a similar problem once, near the middle of a three-way turn out.  It seems that the rails were slightly wider than standard as they curved and sometimes engines lost power going through even though all my frogs were powered.  Spiking the rails into alignment solved the problem.

Jerry
________________________________________________
jerryg2003@...

emrldsky

There is probably a good electrical connection to the track, so it is not that.. Very probably there is a "slight" dip in one or both tracks, so one or more wheels is actually not touching the track. I have run into this a few times. Hold a long straight edge on each rail, individually and look for a gap between the rail and the straight edge.

Peace,
Mike G.

john

It could be track!  I have found a number of Rail Joiners that just don't make good contact. Although rare, it has happened. I have also discovered a number of cold solder joint connections on tracks. It happened more on Brass track than on Nickel Silver but I have them show up occasionally. It even happens inside soldered Rail Joiners too.
Enjoy,
john

On Monday, June 25, 2018 12:09 PM, emrldsky <azMikeG@...> wrote:

There is probably a good electrical connection to the track, so it is not that.. Very probably there is a "slight" dip in one or both tracks, so one or more wheels is actually not touching the track. I have run into this a few times. Hold a long straight edge on each rail, individually and look for a gap between the rail and the straight edge.

Peace,
Mike G.

John Cahill

Ditto but mine was caused by the track being hit with a pin hammer on one side causing it to dip and then lose contact when certain locos entered the section.  Had to replace damaged section.
John

On Mon, Jun 25, 2018 at 12:19 PM, JerryG via Groups.Io wrote:
I had a similar problem once, near the middle of a three-way turn out.  It seems that the rails were slightly wider than standard as they curved and sometimes engines lost power going through even though all my frogs were powered.  Spiking the rails into alignment solved the problem.

Jerry
________________________________________________
jerryg2003@...

Ron Still

Agree with Mike, had this exact problem with Atlas crossing. Drove me crazy till I figured it out!

On Jun 25, 2018, at 10:09 AM, emrldsky <azMikeG@...> wrote:

There is probably a good electrical connection to the track, so it is not that.. Very probably there is a "slight" dip in one or both tracks, so one or more wheels is actually not touching the track. I have run into this a few times. Hold a long straight edge on each rail, individually and look for a gap between the rail and the straight edge.

Peace,
Mike G.

Gary Chudzinski

IMHO, I would never depend on rail joiners for electrical conductivity.  I solder power drops every six feet, in the middle of two three foot sections of flex track soldered together using #18 solid wire (for Code 100 rail) on the outside of the rails. Could also use rail joiners, however, if the joint ever needs to be separated, it's a major unsoldering job! One has to be particularly aware there is power to the turnout's short sections of track exiting an isolated frog. I have yet to have any track power problems using these procedures.

Gary Chudzinki

Gary.. I'd actually suggest feeders at every 3 foot section of track. And for turnouts..I have no problem with Micro Engineering turnouts...and I run DCC/DC with a DPDT switch.

cheers,

On Tue, Jun 26, 2018 at 10:19 AM, Gary Chudzinski wrote:

IMHO, I would never depend on rail joiners for electrical conductivity.  I solder power drops every six feet, in the middle of two three foot sections of flex track soldered together using #18 solid wire (for Code 100 rail) on the outside of the rails. Could also use rail joiners, however, if the joint ever needs to be separated, it's a major unsoldering job! One has to be particularly aware there is power to the turnout's short sections of track exiting an isolated frog. I have yet to have any track power problems using these procedures.

Gary Chudzinki

Jim Gray <n747jg@...>

Just a bit off of the subject, but I am just completing the wiring of a 30' x 20' HOn3 layout using Micro Engineering flex track and turnouts. NCE power for DCC with PSX cbs and PSX-AR auto reversers for loops. Everything is running pretty well, but on occasion my Blackstone locomotives will stall on a random turnout, especially when moving slowly. And often will start moving again on their own after a brief stall. I don’t think it’s a short even though it acts like it might be. Frog polarity is correct, in conjunction with the tortoise, and works fine 95% of the time.

Any ideas what my issue might be? Or is this just the nature of the beast?

Thanks!

Jim Gray
Denver, CO

Don Vollrath

Jim, If other equipment stays energized it is not a short circuit but an open one. Turn on the headlight and make it crawl through in either orientation or direction. If the light goes off, you lost power to the loco. Look for a poor or intermittent electrical connection to the movable point rails as the loco rolls through. Look also for a vertical bump that lifts the loco wheels off the rails.

DonV

Glenn

We experience a similar problem on a friends 25-year old layout. The layout was built with Atlas and later with some Shinohara turnouts. DCC was employed a few years after. Because the layout was built as DC all four rails on the frog side of the turnouts have insulated joiners.

There are two NCE EB3's involved, however neither indicated a short. Testing with a meter is almost impossible as the engine restarts before a meter can be used.

The problem happens mostly with 6-axle diesels and one or two 8-coupled steam engines. Four turnouts act up. Three are Atlas, but only one turnout in a Shinohara double crossover. Engines stall on the turnout then restart most often without human assistance.

The diesels are mostly DCC-ized Athearn 6-axle engines. But not all have the problem. The steamers are Broadway Limited 4-axle. Before I put the decoders in, the diesels sat on the shelf for at least ten years. I used NCE basic decoders. The original motors were left in.

Of course the problem never occurs when you are eyeballing the site.

Oddly enough, I had put a decoder into an old Penn-line 4-wheel Plymouth diesel, it has no problems navigating the turnouts.

Glenn

-----Original Message-----
From: Jim Gray <@747>
Sent: Jun 27, 2018 9:43 AM
To: w4dccqa@groups.io
Subject: Re: [w4dccqa] Dead track area dcc
Everything is running pretty well, but on occasion my Blackstone locomotives will stall on a random turnout, especially when moving slowly. And often will start moving again on their own after a brief stall. I don’t think it’s a short even though it acts like it might be.

Jim.. have you tried cleaning the track? I have a bright boy at the ready... could be something as simple as that! Just a suggestion.

On Wed, Jun 27, 2018 at 9:43 AM, Jim Gray wrote:
Just a bit off of the subject, but I am just completing the wiring of a 30' x 20' HOn3 layout using Micro Engineering flex track and turnouts.   NCE power for DCC with PSX cbs and PSX-AR auto reversers for loops.    Everything is running pretty well, but on occasion my Blackstone locomotives will stall on a random turnout, especially when moving slowly.  And often will start moving again on their own after a brief stall.  I don’t think it’s a short even though it acts like it might be.   Frog polarity is correct, in conjunction with the tortoise, and works fine 95% of the time.

Any ideas what my issue might be?  Or is this just the nature of the beast?

Thanks!

Jim Gray
Denver, CO

btw.. my system is NCE Power cab too. I've replaced all my old Shinohara turnouts and the newer Atlas as the points are too loose...I like to hand throw them as I have a switching layout. Lance Mindheim has a lot of knowledge about that. www.lancemindheim.com

On Wed, Jun 27, 2018 at 2:31 PM, Brad Ketchen wrote:
Jim.. have you tried cleaning the track? I have a bright boy at the ready... could be something as simple as that! Just a suggestion.

On Wed, Jun 27, 2018 at 9:43 AM, Jim Gray wrote:
Just a bit off of the subject, but I am just completing the wiring of a 30' x 20' HOn3 layout using Micro Engineering flex track and turnouts.   NCE power for DCC with PSX cbs and PSX-AR auto reversers for loops.    Everything is running pretty well, but on occasion my Blackstone locomotives will stall on a random turnout, especially when moving slowly.  And often will start moving again on their own after a brief stall.  I don’t think it’s a short even though it acts like it might be.   Frog polarity is correct, in conjunction with the tortoise, and works fine 95% of the time.

Any ideas what my issue might be?  Or is this just the nature of the beast?

Thanks!

Jim Gray
Denver, CO

Puckdropper

If you drop feeders at the end of each track, you can skip every other joint and wind up with feeders every 6' while still following the "one per piece of rail" rule. This gives you another advantage in that the bus only needs to be stripped once to solder on two feeders.

Being the peculiar lazy sort that I am, I just dropped feeders on either side of every rail joiner and attached them to the bus. More physical effort for less memory effort. It doesn't really take all that long to do the extra feeders.

Another trick: Leave the feeders above the layout until you're ready to wire them. Using 22-26 gauge wire, you can loop the wire into the hole but not pull it all the way down yet. After you wire it to the bus, give it a gentle pull and the feeder will pull into the hole. Your eyes are better at seeing feeders above the track than they are seeing them below!

Puckdropper

On Wed, Jun 27, 2018 at 06:09 am, Brad Ketchen wrote:

Gary.. I'd actually suggest feeders at every 3 foot section of track. And
for turnouts..I have no problem with Micro Engineering turnouts...and I run
DCC/DC with a DPDT switch.

cheers,

On Tue, Jun 26, 2018 at 10:19 AM, Gary Chudzinski <chudgr@...> wrote:

IMHO, I would never depend on rail joiners for electrical conductivity. I
solder power drops every six feet, in the middle of two three foot sections
of flex track soldered together using #18 solid wire (for Code 100 rail) on
the outside of the rails. Could also use rail joiners, however, if the
joint ever needs to be separated, it's a major unsoldering job! One has to
be particularly aware there is power to the turnout's short sections of
track exiting an isolated frog. I have yet to have any track power problems
using these procedures.

Gary Chudzinki

Bill Wilken

I’ve found 3M “suitcase” connectors make the job even easier. No need to solder anything underneath benchwork. Similarly, if you tin the track end of the jumper, soldering it to the rail is quick, easy, and clean

On Jun 28, 2018, at 5:06 PM, Puckdropper via Groups.Io <puckdropper=yahoo.com@groups.io> wrote:

If you drop feeders at the end of each track, you can skip every other joint and wind up with feeders every 6' while still following the "one per piece of rail" rule. This gives you another advantage in that the bus only needs to be stripped once to solder on two feeders.

Being the peculiar lazy sort that I am, I just dropped feeders on either side of every rail joiner and attached them to the bus. More physical effort for less memory effort. It doesn't really take all that long to do the extra feeders.

Another trick: Leave the feeders above the layout until you're ready to wire them. Using 22-26 gauge wire, you can loop the wire into the hole but not pull it all the way down yet. After you wire it to the bus, give it a gentle pull and the feeder will pull into the hole. Your eyes are better at seeing feeders above the track than they are seeing them below!

Puckdropper

On Wed, Jun 27, 2018 at 06:09 am, Brad Ketchen wrote:

Gary.. I'd actually suggest feeders at every 3 foot section of track. And
for turnouts..I have no problem with Micro Engineering turnouts...and I run
DCC/DC with a DPDT switch.

cheers,

On Tue, Jun 26, 2018 at 10:19 AM, Gary Chudzinski <chudgr@...> wrote:

IMHO, I would never depend on rail joiners for electrical conductivity. I
solder power drops every six feet, in the middle of two three foot sections
of flex track soldered together using #18 solid wire (for Code 100 rail) on
the outside of the rails. Could also use rail joiners, however, if the
joint ever needs to be separated, it's a major unsoldering job! One has to
be particularly aware there is power to the turnout's short sections of
track exiting an isolated frog. I have yet to have any track power problems
using these procedures.

Gary Chudzinki

Gary Chudzinski