# Voltage drop question



## bryher (Dec 17, 2011)

So my layout suffers from that common problem where the engine speeds up and slows down depending on how far it is from the power lock on. I've ready about this issue and ways to address it but still unable to get it to work.

I have two separate layouts. Both have switch tracks but still operate a single train and one power lockon/section. Some accessories are wired using the accessory terminals.

I believe an easy way is to simply run another set of wires from the same transformer posts to another lockon close to the area where the power drops. I've done that and it didn't do a thing. Its not that it helped a little, it didn't change at all.

So next I did the only other thing I could think of. I took a multi meter and tested various sections of the track using the AC meter and touching one lead to the inside rail and one to the outside. Unless I'm doing something wrong it seemed like there was no voltage drop anywhere.

I ran different engines, with and without carriages, and the same happened. Im using an older Z type transformer from the 50s and also a newer lionel one from a set bought in 2002. 

Could it be something else?


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## rkenney (Aug 10, 2013)

Your readings are correct. There is no voltage drop until current flows. You will need a load placed on the track where you want to measure the voltage drop. Voltage across the load will vary depending on the poor connection (another load) it is in series with.

A Dummy load can be approximated with an automotive bulb.

Current remains the same in a series circuit, voltage will drop across each load (the sum of all loads being equal to the supply voltage).

Hope this helps. Usually its easier to just add more lock-ons till the problem stops.


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## teledoc (Oct 22, 2014)

It sounds like you have poor continuity near the area where the engine slows down, then speeds back up. That can be from corroded track pins, or just a plain loose connection. This is assuming you are usingtubular track. What type of track are you using??? 

You also mention you have two separate layouts, but exactly how is your layout set up?? Are they connected together in anyway, or is it one layout within, or above the other, an TOTALLY Separate?? Also, is the track nailed or screwed down? What size wire are you using to feed the track? 

Answer those questions, and we can work from there to a solution.


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## Lee Willis (Jan 1, 2014)

The first thing: is their any other reason why a train would slow down where it is slowing down, such as: a) it is a tight curve - trains slow down on tight curves, or b) it is an incline and the train has to climb.

If not, you have possibly a bad conector between track sections, or the feeder wire you ran to the place it was slowing down was too thin a wire.


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## bryher (Dec 17, 2011)

rkenney said:


> Your readings are correct. There is no voltage drop until current flows. You will need a load placed on the track where you want to measure the voltage drop. Voltage across the load will vary depending on the poor connection (another load) it is in series with.
> 
> A Dummy load can be approximated with an automotive bulb.
> 
> ...


Ah! thanks I had no idea. FYI I did put the lockon first where the train slowed, then where it sped up. And in between. no fix.



teledoc said:


> It sounds like you have poor continuity near the area where the engine slows down, then speeds back up. That can be from corroded track pins, or just a plain loose connection. This is assuming you are using tubular track. What type of track are you using???
> 
> You also mention you have two separate layouts, but exactly how is your layout set up?? Are they connected together in anyway, or is it one layout within, or above the other, an TOTALLY Separate?? Also, is the track nailed or screwed down? What size wire are you using to feed the track?
> 
> Answer those questions, and we can work from there to a solution.



Both layouts are definitely separate, not connected in any way. One is within the other but not connected. The track is screwed down with random machine screws I had laying around. 

Since these questions have mixed answers I'll answer based on the layout...


Layout #1 - this layout is an oval with 4 switch tracks and a X/cross track in place. Its completely closed. 

Track type: I actually use both O and O27, (that's the smaller, lower profile O size right?). 95% of the track is O27 but 2 of the switches and the X/Cross piece are O. The other two switches are O27. None of them are wired at all. The two O switches have fibre pins on the same outside rail.


Wiring: Here I'm using smaller 22-24 gauge wire in both lock-ons.

Power: using a newer lionel power pack from a set I received in 2002. I basically twisted the wires together from the pack and ran them out to the two lock-ons. 


Layout #2 - this is a smaller piece that runs in a couple tight turns and has two switch tracks to open ended branches, meaning the branch lines stop with bumpers and the train has to back up to get out.

Track type: its all O. 

Wiring: Here I'm using larger 16 g wiring on the lock-on. 

Power: using an older ZW 250 W model. 


I think next I'll take a picture to show the actual layout and point out where exactly the power drops.


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## Lee Willis (Jan 1, 2014)

222-24 gauge wire is pretty small. That is probably part of your problem. 

16 gauge is better but I always use 12 gauge or bigger. Definitely helps to have big wire.


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## teledoc (Oct 22, 2014)

Is the voltage drop on both loops, or just one?? Does it occur near a curve, or in a straight section? Is the problem on layout #1, which it may be. If it is in layout #1, you need to increase the wire size. The 22/24 Gauge is WAY too small!! A bare minimum would be 18, preferably 16 ga. There is too much resistance with the small gauge wire.

As Lee has pointed out, the small 22-24 gauge wire just won’t cut it asa feeder. For a small loop, 18 would be minimum. A moderate loop should have 16, and a large loop, or lots of track, I would use 14, & preferably 12 Gauge.

I’ll explain what I think you should do, after the answer to above question, of both loops, or just one. We’ll get you fixed.


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## teledoc (Oct 22, 2014)

If you look at Lee Willis’ layout, you can understand why he chose 12 Gauge, as his layout is large. The track connections with track pins is crucial, that they are tight, with NO lose connections. When you run your train with the small wire, does the wire feel hot, or very warm. Does the spot where the loco slows down feel hot?? That is a surefire indication that you have a lot of resistance, causing the loco to slow down.


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## bryher (Dec 17, 2011)

Lee Willis said:


> 222-24 gauge wire is pretty small. That is probably part of your problem.
> 
> 16 gauge is better but I always use 12 gauge or bigger. Definitely helps to have big wire.


Thanks Lee. I always thought so. But the set I received in 2002 has really small wires coming from the power pack, like 22-24 gauge (will have to measure) so I figured it was fine. Also if the lead wires from the pack are small does it matter if the wires connected to them are larger?


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## teledoc (Oct 22, 2014)

The other transformer you have, which is it, the “Z” or the “ZW”? Either way, they both will run 4 trains, as there are 4 controls. Pick another set of binding posts and connect that to the loop you have running off the small power pack.


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## bryher (Dec 17, 2011)

teledoc said:


> Is the voltage drop on both loops, or just one?? Does it occur near a curve, or in a straight section? Is the problem on layout #1, which it may be. If it is in layout #1, you need to increase the wire size. The 22/24 Gauge is WAY too small!! A bare minimum would be 18, preferably 16 ga. There is too much resistance with the small gauge wire.
> 
> As Lee has pointed out, the small 22-24 gauge wire just won’t cut it asa feeder. For a small loop, 18 would be minimum. A moderate loop should have 16, and a large loop, or lots of track, I would use 14, & preferably 12 Gauge.
> 
> I’ll explain what I think you should do, after the answer to above question, of both loops, or just one. We’ll get you fixed.



The drop is definitely on both of them. 

Here's an aerial photo of the entire layout. The outer loop is where the silver passenger train is. The inner loop has the log loaded and two branches. 










On Layout #2 is where I have the smaller gauge wires in two places. 

Here's a video showing the entire layout and layout #2 running.






Here's a closeup of where the train begins to slow











I have pics and videos of layout #1, the outer loop next. 

to your guys points my joints are good but not perfect, so probably losing alot there. But why would it suddenly just stop, and on such a small loop?

PS - are my pictures coming up? I feel like they dont show when I post them. Maybe a limit on my account until I have more posts?


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## bryher (Dec 17, 2011)

teledoc said:


> The other transformer you have, which is it, the “Z” or the “ZW”? Either way, they both will run 4 trains, as there are 4 controls. Pick another set of binding posts and connect that to the loop you have running off the small power pack.


Its ZW. Ok will try that. See what happens (PS this has happened to me for years since I dug these trains up and started to run again. Its not like its something special with this layout. Its me!!)


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## bryher (Dec 17, 2011)

teledoc said:


> If you look at Lee Willis’ layout, you can understand why he chose 12 Gauge, as his layout is large. The track connections with track pins is crucial, that they are tight, with NO lose connections. When you run your train with the small wire, does the wire feel hot, or very warm. Does the spot where the loco slows down feel hot?? That is a surefire indication that you have a lot of resistance, causing the loco to slow down.


Ok I havent checked to see if the wires or track feels hot. Will do that next. As far as the connections I def have loose ones and not completelty flush at all times. Wouldn't this result in just slowness across the board? or would this cause these big spikes and dips as shown in the video?


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## teledoc (Oct 22, 2014)

Okay, just watched the video, and the slow down occurs at the curves. One thing I notice, is the curved section, at far side in video, looks really tight and should have maybe a half section of track placed at top of curves. The section nearest in view, at end of video is probably loose track pins. You will most likely have to unscrew the track, so you can check the connections.


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## bryher (Dec 17, 2011)

teledoc said:


> Okay, just watched the video, and the slow down occurs at the curves. One thing I notice, is the curved section, at far side in video, looks really tight and should have maybe a half section of track placed at top of curves. The section nearest in view, at end of video is probably loose track pins. You will most likely have to unscrew the track, so you can check the connections.


Ok so the tight curves can cause a loss in the connection of the engine to the tracks?

And I'll check the connections on the other part of the track near the end of the video.
thanks!!


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## bryher (Dec 17, 2011)

Here's some better videos of both layouts, from the point of where they slow to a crawl...


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## mopac (Feb 24, 2011)

No, tight curves just have more resistance (not electrical resistance) against the wheels.
Scrubbing I guess you could call it.


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## highvoltage (Apr 6, 2014)

mopac said:


> No, tight curves just have more resistance (not electrical resistance) against the wheels.
> Scrubbing I guess you could call it.


Exactly. It's mechanical resistance, or friction. The wheels are pushed against the rails, which causes slowdowns.


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## teledoc (Oct 22, 2014)

Mopac & HIghvoltage, Thanks for adding the extra explanation. The curve is too tight of a curve to maneuver, and needs to be smoothed out to a wider arc. What you show, is a tight arc.


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## bryher (Dec 17, 2011)

Ok so playing devils advocate then wouldn't a complete circle made up of 100% curve tracks be the absolute tightest? Would we expect my train to run this slow in a 100% curved circle layout ?

Or is it the combination of a left curve with a right curve?

So right now I'm in the process of stepping back and simplifying things to isolate the problem . To start I've unscrewed wall tracks from the surface and am in the process of making the tightest possible joins for each connection. Makes it challenging where I have O gauge and O27 combines together (SWITCHES and cross track are O). But so far no real problems. Will test and remove switches if needed and just start with a simple loop first.


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## bryher (Dec 17, 2011)

UPDATE:

Ok I think I need to take a break from this thread and go waaay back to the basics. I did the above and was experiencing some really strange stuff. So I've removed all switch tracks except one which has nothing connected to the branching part of the switch. I've removed all screws so track is not secured down. Things are better but inconsistent.

So I guess my question now is: can someone point me to a couple of good threads and/or web links to learn more about basic voltage, power consumption, testing with a multimeter? I feel like I'm lacking in this area which is making things more confusing.


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## rkenney (Aug 10, 2013)

Basic Circuit Troubleshooting


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## Lee Willis (Jan 1, 2014)

bryher said:


> UPDATE:
> So I guess my question now is: can someone point me to a couple of good threads and/or web links to learn more about basic voltage, power consumption, testing with a multimeter? I feel like I'm lacking in this area which is making things more confusing.


I'm sure someone can. You might look on Classic Toy Trains website for books Kalmbach sells on model train layouts. 

But really, I'd suggest just starting a new thread with the basic questions you have. 

I watched your videos several times. Some of the slowing down is probably natural - you have several places where it looks to me like a train would slow down even if voltage were constant. But I also saw at least one place where speed didn't recover as quickly as I think it should when the loco pulled out of a tight curve. You have a very complicated layout actually, with tight curves and switches, so it is normal, I think, to expect some of the problems you have. 

And don't be embarrassed to ask stupid questions, because there are no stupid questions: keep in mind that at some point in the past, everyone answering your questions didn't know that answer - they learned, and you will too. 

As a start in that direction, my advice. Nuke it with lots of big wire! By which I mean wire and lockons (or solder) is cheap, so "overdo" things a lot and you will have no problems that cause you the type of grief you have been having - ever. 

I use lots of feeder wires to different places on the track, and use big wire everywhere. There are 335 feet of track on my layout. That track is feed at over fifty places by feeder wires soldered onto the rails. I don't use anything smaller than #12 wire even though #18 would often do, and in some cases I use #8 (which is so big it isn't that easy to solder). This is all way more than needed. But I have no measurable voltage drop under 10 amps of current flow anywhere on the layout, and never have any electrical problems.


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## bryher (Dec 17, 2011)

Thank you 

@rkenney - I'm going to read that link as soon as I'm done with this post 

@Lee - thanks for the advice and confidence boost. I was really seeing some strange things so yea will start a new thread with basic questions

On the layout LOL yea it's a little crazy  each year I let my son (Now 9) design the layout. And then I take the challenge. Great fun but hilarious to see how his mind thinks. But good to know some parts can lead to slowdowns 

On the wiring. Awhile back I purchased 14g stranded wire. The only thing I don't like is it's so hard to tighten into the power pack terminals and the lock ons. But to your advice that's what I'll use going forward. Im a decent solderer so that part doesn't intimidate me. I'll plan to solder directly to the track in multiple places along the layout to start.

I'll leave with one last question: if the wire coming out of a power pack that was included in a Lionel set I have is really small like 22g does it even do anything using say 14g after that? In other words if the power starts out on 22g will using 14g after that point do anything?


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## highvoltage (Apr 6, 2014)

bryher said:


> ...I'll leave with one last question: if the wire coming out of a power pack that was included in a Lionel set I have is really small like 22g does it even do anything using say 14g after that? In other words if the power starts out on 22g will using 14g after that point do anything?


If most of your wiring is 14 gauge but only a small part is 22 gauge, you are effectively running a large capacity wire for most of the circuit. The small amount of 22 gauge wire in the circuit will have a minimal impact.

Wire resistance is measured in ohms/foot. 14 gauge has a smaller resistance (less ohms/foot) than 22 gauge. If your entire circuit is 22 gauge wire, then the resistance would be higher and the voltage drop would increase. But if your circuit is 90% - 14 gauge and 10% - 22 gauge then your overall resistance is reduced.


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## BENZ TRAINZ (Sep 22, 2017)

i watched your video, the problem is your track, not the transformer not the layout. there are two ways to correct this, first use a small file, emery board or razor blade and scrape *every pin on the track*. scrape the center rail with a butter knife to remove the oxide, CLEAN THE TRACK WITH 90+% ALCOHOL. clean the wheels and contactor on the engine. you cant cut corners on this. you either have good conductivity in your track or you dont. dirty track and poor connections always manifest in slow spots and acceleration near the lockon. 

you can use bipolar power application. attach a wire to the center rail on the far side of the layout, attach a wire to the inside rail on the near side of the layout. that will eliminate the hot spots and should give you constant speed all the way around.

with a bipolar connection your not applying power to one spot with a lock on, your applying power to the entire track on two different sides. your available power will be limited by the *total resistance *of your track. you wont have any hot spots as long as your track is in good condition with good electrical connections the engine will run at a constant speed. *there is no shortcut to clean track.*


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## BWA (Jun 16, 2012)

Surprised no one has mentioned pin bending yet......

Bending the center pin, and, either (not both) of the outer rail pins slightly towards each other helps tremendously with electrical (and mechanical) connection between track pieces......

Don't over do it, just one or two degrees in each pin/rail.

As you slide the track together, the slight sideways pressure from the bend helps the pin cut through any possible corrosion/dirt inside the rail, plus, having that constant sideways pressure helps keep the pin in contact with the inside of the rail......


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## bryher (Dec 17, 2011)

BENZ TRAINZ said:


> i watched your video, the problem is your track, not the transformer not the layout. there are two ways to correct this, first use a small file, emery board or razor blade and scrape *every pin on the track*. scrape the center rail with a butter knife to remove the oxide, CLEAN THE TRACK WITH 90+% ALCOHOL. clean the wheels and contactor on the engine. you cant cut corners on this. you either have good conductivity in your track or you dont. dirty track and poor connections always manifest in slow spots and acceleration near the lockon.
> 
> you can use bipolar power application. attach a wire to the center rail on the far side of the layout, attach a wire to the inside rail on the near side of the layout. that will eliminate the hot spots and should give you constant speed all the way around.
> 
> with a bipolar connection your not applying power to one spot with a lock on, your applying power to the entire track on two different sides. your available power will be limited by the *total resistance *of your track. you wont have any hot spots as long as your track is in good condition with good electrical connections the engine will run at a constant speed. *there is no shortcut to clean track.*


Ok this is all new stuff to me, and it all sounds like it would work, so I like it! And makes alot of sense b/c 90% of the track I have is very old, my father in laws who's owned the set since the 40s. When he gave it to me to hold onto I started the restoration process. For the track I went to town using scotch brite pads. But that was it. Original pins. Alot of the track is not in good shape. 

Some questions on the filing and scraping of pins: 

- what am I looking for to know its good? 

- And do I just scrape the top surfaces or all around, like on the pins? Maybe I'm better off buying all new pins? 

- on the center rail, is file or butter knife better than scotch brite pads? 

As far as the bipolar power to echo BWA Ive havent come across this yet as the standard. I can easily do this. So does this mean its constant and I cant vary the speed with the controller?


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## BENZ TRAINZ (Sep 22, 2017)

you can still vary the power, what i meant was the engine wont speed up or slow down, it will run at a constant speed all the way around the track. this depends on how corroded your track is.

scrape every pin to remove the oxide, you will see bare metal when you scrape it. scrape the center rail with a butter knife. this oxide is hard a scotch bright wont remove it, it polishes it. *CLEAN YOUR TRACK* before you do anything else. clean the locomotives wheels and contactor. forget about bending pins to make a good connection, that is a layman's expedient, that is not the way to get a good connection in your track.

once the pins and center rail are clean you will see an instant and spectacular difference in how your engine will run. here is a video on scraping the center rail, it does not have to be sharp you just want to scrape the oxide off. just doing this will increase the efficiency of your track instantly.


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## rke930 (Jan 9, 2014)

Hello everyone. I've been following this board for a couple of years but haven't posted anything because I come here to learn, and I've learned a lot! I'm eternally grateful for the expertise available on this board.

Regarding the bipolar power system, I hadn't heard about this before either. But, I tried it on my Christmas layout and OMG!, it works! This is a revelation - thank you Benz! I don't know why this isn't more widely known. And thank you (again) Benz for the best instructions I've seen on how to properly clean track. I'm realizing, at long last, that clean track is critical to good operation. Who knew? Everyone but me, I guess.


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## teledoc (Oct 22, 2014)

Rke930, Welcome to MTF, as a new member. Do not feel intimidated with asking a question, if you don’t know the answer. The only stupid question, is the one NOT asked. We have a very diverse group, covering multiple aspects, as you have noticed. Join in to whatever group you are comfortable with.


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