My railroad was running fine. Then I put in a highway grade crossing and ballasted the last section of mainline track. I created a simulated asphalt crossing by paving over the tracks with joint compound and carving out the flangeways before the compound had completely hardened. I'd seen Linn Westcott demonstrate this technique on a PBS series he did about thirty years ago and I had successfully used it on my last layout. After painting the roadway, I then went to scrape the rails clean before conducting my first test runs. As I was cleaing one of the rails, my whole DCC system shut down as it is designed to do when it detects a short. It's easy to tell when that happens because all my sound equipped locos shut down.
I tried to power it back up but it refused. I went completely around the layout and looked for the usual causes of a short, derailed cars, metal tools inadvertently laid across the tracks (Don't ask how often I have done that). I even found a dead mouse laying on the tracks that I thought might be the culprit, be that didn't solver the problem. Then I got to thinking what had changed. I had introduced a number of new materials to the tracks. Ballast, joint compound, and paint. My first thought was that these materials wouldn't likely be the cause but then the thought hit me that the joint compound, glue, and paint are water based and perhaps there is still residual moisture in these materials that is creating an electrical connection between the rails. This isn't a hard short like I would get if I lay a metal tool on the rails. The short occured when I was cleaning the rail tops and on several occassions I could get the system to power back up for a few seconds before shutting down. This leads me to believe whatever is causing the short might be a material that isn't a great electrical conductor but good enough to create a short after a few seconds. Does that sound like it could be the cause and could I expect this problem to go away in a few days after everything completely dries?
Another thing I should add is that the grade crossing is very close to a mainline crossover which uses Walthers turnouts. These turnouts must be insulated from the power source at the diverging end or they will cause a short. I wonder if any of the new materials I added to the track could have caused the insulating gap between track sections to be bridged.
Electricity is not my strong suit. I know just enough to be dangerous so I would appreciate any advise from those who are more knowledgeable in these areas.
Ballast, joint compound, and paint should be nonconductors (insulators) WHEN DRY. Definately make sure the materials are all dry. Also, since this happened when you were scraping the rails, I suggest running a vacuum cleaner over the area, and a couple feet on either side of the area.
Also, if you even suspect the insulators at the crossover, give this area a close inspection
I know that some paints used to contain high levels of lead,may be it is still the case.Were these levels enough to be conductive?Can't say.Or is it the joint compound?May be worthed investigating,ther may be some conductive matter (lead,aluminum,etc) within one of your products.Just a guess......
Given that this is only the change you made to the layout, I'd suspect the still-wet materials. I've heardof this also happening when ballasting the track - while wet the minerals in the ballast are just conductive enough to cause a short. There are sometimes also interactions between paint and other materials. Let everything dry thoroughly and try again. Check the turnouts to make sure nothign is bridging the insulation. Even a slight speck of wet plaster materials can be enough.
A dead mouse? Don't run trains that often? Oh no, better ban DCC, it electrocuted a mouse! LOL
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks for the replies. While waiting for someone to respond, I decided to do some further investigating. First, I cut power to the district that contained the new work but the problem persisted. I cut power to a second district and continued to have the problem although after doing that, the system would stay powered up for several seconds before shutting down. Finally, I cut power to my roundhouse where I had about a dozen idling locos. Bingo!!! I am wondering if it might be a case of system overload. When I first started up in DCC, I had read that if too many locos are running off the same power source at one time, it could cause an overload but I was only attempting to run one loco during the test. Now the sound locos are drawing power to make the various sounds while they idle but could this draw enough power by itself to cause an overload. I have had this many locos idling at the same time in the past without a problem so it seems strange that this would suddenly become a problem. I have not had a chance to repower the district that I first suspected to see if that is going to be OK. At this point, I don't know if I have one problem or two. Actually, I might even have a third problem. My wireless throttle began acting up at the same time and I don't know if it is related. After getting the main system to stay powered up, the problem persists with my CVP wireless throttle. The direction lights are both blinking at me and I've never seen that before. I'm going to have to dig up the manual and figure out what that is telling me. Other than that, everything is running fine.
How large are your buss wires? Do you have enough feeders? How many locos in the round house? Is this a five amp system? Have you done a quarter test around your whole layout?
If your going to have more than 10 sound equipped locos in the RH district than you may need a booster just for that district. Is your booster/ command station running cool enough?
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
locoi1sa How large are your buss wires? Do you have enough feeders? How many locos in the round house? Is this a five amp system? Have you done a quarter test around your whole layout? If your going to have more than 10 sound equipped locos in the RH district than you may need a booster just for that district. Is your booster/ command station running cool enough? Pete
The bus wires are 14 gauge. I have 14 stalls in the round house district and recently most of them have been filled, probably 3/4 of them with sound locos. The RH stalls are wired to two seperate terminal strips which each have a feeder to the bus. I'm trying to understand why that would be an issue with the DCC system. Wouldn't the electrical draw be the same regardless of how many feeders are used to attach to the bus wire. I can understand how the feeder wires might become overloaded but why would that affect the system. Also, I'm trying to understand why that would suddenly become an issue. I had recently added one more sound loco to the layout (a 4-6-0), but when I began having problems, I started removing some of the locos from various places on the layout which should have taken the amount of power being drawn to below the level it was at when the system was running fine. I would think that if the sound equpped locos were causing an overload, it would have happened long before now. As I said, everything was running fine until I added the grade crossing.
jecorbett The bus wires are 14 gauge. I have 14 stalls in the round house district and recently most of them have been filled, probably 3/4 of them with sound locos. The RH stalls are wired to two seperate terminal strips which each have a feeder to the bus. I'm trying to understand why that would be an issue with the DCC system. Wouldn't the electrical draw be the same regardless of how many feeders are used to attach to the bus wire. I can understand how the feeder wires might become overloaded but why would that affect the system. Also, I'm trying to understand why that would suddenly become an issue. I had recently added one more sound loco to the layout (a 4-6-0), but when I began having problems, I started removing some of the locos from various places on the layout which should have taken the amount of power being drawn to below the level it was at when the system was running fine. I would think that if the sound equpped locos were causing an overload, it would have happened long before now. As I said, everything was running fine until I added the grade crossing.
If possible, remove all locos, passenger cars with lights, EOT devices, etc. Check your wiring under the layout to make sure you have no bare wire touching anywhere it shouldn't. Check each district or isolated section with an ammeter to make sure you do not have some strange current leak between the rails anywhere. Especially make sure to check the area with the grade crossing.
For example, I have seen situations where dirt and carbon deposits can clog frogs and create a sort of resistor on layouts where the frog point scraped the dirt off the rolling stock wheels. In this case the turnout was in a hard to reach area and the owner did not clean it often (if at all). This was a rare case, but it shows anything is possible when looking for a strange problem.
Carl in Florida - - - - - - - - - - We need an HO Amtrak SDP40F and GE U36B oh wait- We GOT THEM!
I asked how large your Buss wires were because if they were too light than they themselves will cause problems like acting like a fuse instead of a wire. Please answer the other questions. That way we can get a better understanding and help diagnose the shut downs instead of guessing.
I have sound locos that draw almost a 1/2 amp just idling with its lights on. I also have a Bachmann 2-8-0 that draws almost a full amp working and spikes over an amp with the whistle blowing. I also have sound locos that draw next to nothing at rest.
How many amps does your booster put to the rails? Are you sure the district with the new grade crossing is really disconnected? Are both rails insulated or just one?
My friend broke his layout into 4 districts on the buss with breakers but on one section the rails were not gaped at the right spot and bridged across 2 breakers. That took some head scratching to find.
I FOUND IT!!!
I had recently wired the junction to my branchline and had inadvertently connected a feeder wire to the diverging end of a Walthers turnout. These can only receive power from the point end. The reason I did not suspect that immediately is because I had wired it about a week before and the layout continued to operate reliably. I'm guessing it had something to do with the turnout allignment. I'm not 100% certain but as near as I can figure, the short is only created if the turnout is alligned a particular way.
To answer Pete's questions, I use 14G bus wire with 18G feeders. I have a Lenz 100 system and us Atlas Generators and CVP remote throttles. Originally, I had a basic Atlas system and converted to Lenz because it was compatible with the CVP remote, but I continued to use the Atlas Generators for power. The Generator did get warm to the touch when I was having problems and that seems to have gone away. I spent the better part of yesterday locating the problem and now have to go back and reattach a number of feeder wires I disconnected during the debugging process. Hopefully, I only had this one problem.
That's great news. The Lenz/CVP combo is the same as our clubs system. Very good system for sure. On the CVP throttles there is a little known glitch that will kill your batteries if you leave the dials on 0 even if the switch is off. I have some locos that the numbers end in double 0 and was wondering why my batteries were going dead. CVP told me of this glitch.
Glad you found the problem.
locoi1sa That's great news. The Lenz/CVP combo is the same as our clubs system. Very good system for sure. On the CVP throttles there is a little known glitch that will kill your batteries if you leave the dials on 0 even if the switch is off. I have some locos that the numbers end in double 0 and was wondering why my batteries were going dead. CVP told me of this glitch. Glad you found the problem. Pete
Thanks for your help, Pete. During the process, I did learn a few more things about DCC. That's a good tip about the CVP throttle. I do have one loco with a 5200 address so I have to make a mental note not to leave it addressed to that loco. I use rechargeable batteries so it would be more of a nuisance if this were to happen. I'm so absent minded that I frequently shut down operations and leave the CVP throttle powered on. I'd end up in the poor house if I had to buy new batteries everytime I did that.
Since you have soo many sound engines, you might want to consider installing block switches at each stall and turn them on when you're ready to run a particular engine. Having that many sound loco's sitting idle reduces the available power to the rest of the layout. Good Job finding the culprit.
Springfield PA