Here’s the issue: The entire layout runs fine. While operating there are 2 locations where the locomotives randomly top. Sometimes they stop at these locations and sometimes not, but it’s always the same location two locations. When the locomotive stop, all the trains stop, and the layout “acts like a short circuit” but then after a couple seconds everything starts running again. Layout: NCE DCC Power Pro 5 AMP, two NCE reversers set for 2 amp trip (both reversing sections work absolutely
fine), two AIUs for block detection with 24 blocks that are all working properly.
The weird thing is i’ve check all the track feeds and they all are on the proper side of the tracks. The location the locomotives stop is at a block transition, but both blocks have a shared ground (I only isolate the blocks on the hot side) and the locomotives (after stopping) just start again so it can’t be a short.
I’ve checked with a meter, everything looks ok.
Can’t for the life of me sort out what’s going on… Any thoughts?
The fact that all of the locomotives stop is a clear indication of s short. If you have no circuit breaker protection (power districts), then the booster will be shutting down the entire layout. So the issue is likely a wiring problem, insufficient or incorrectly placed gaps, or a problem with an auto-reverser. The question is which is the culprit?
it’s not a classic “short” as it doesn’t shut down the system. It stops the system for a second or 2 and starts right up again with the locomotive in the exact same spot. If it were a short, it would not start again, and it wouldn’t be intermittent. it would short at that spot every time and not clear itself. Auto reversers are operating exactly the way they are supposed to do. I’m thinking more about any stray voltage or something else that requires time to develop. The stop point is in the standard block with no trains in the reversers and the other location is also at a block transition… again. it doesn’t just short out. it “shorts” out for a second or 2 then keeps right on going. This problem is rather unique and not a typical issue.
At the risk of sounding like a simpleton, have you thoroughly cleaned the track in those locations. The fact as you stated that after a few seconds the layout then runs properly, that suggests to me a dirty track momentary short.
Same spot means a problem with the track. Sounds like a dead spot to me. Clean the track, including inside the points and where the tracks connect together for the turnout.
i’ve seen similar symptons for 2 reasons on the club layout:
there was a broken feeder when the loco reached the track fed by the feeder and i’ll guess that the weight of the loco pushed the track down onto the feeder but it took a moment for the decoder to come up and see a speed command.
Ah, missed the point about all going dead for a few seconds. On my system (Digitrax), a momentary short does not necessarily shut down the entire system. All stops, but if the loco has enough momentum, it gets through without having a system shutdown.
so there is a gap at that point in the photo and your “standard block” is acutally 2 blocks
what is to the right of that “point” in the photo?
i think it would help to see more of the track plan, especially where the blocks are
Up date… It wasn’t the track… it’s two specific locomotives. I’m assuming its something about the decoders…( all the locomotive have 6 drive wheels ) It happened to be the first two I tried… Out of annoyance I tried another locomotive and … no issues… then another… no issues… then I ran a third for over an hour changing directions, using one or both of the reversers… works perfectly… go figure… Now I have to figure out which decoders they are and why. I Need to also double check these areas to see if the two locomotive problem children may have a chassie / track interface issue.
thanks for the assist everyone. I appreciate the support.
FYI the block ( block 6 in this case ) rus from the left upper track at the gap thru both switches and out at the bottom right. BLock 5 runs from the upper gaps and off to the layout. The reverser at the bottom runs from the gap , 6 feet and connects again. The other reverser section , on the right, runs 3 feet and connects again with block 5 completing reverser section. I narrowed it to two locomotives, all the other locos I have run fine through the area with no issues… so it’s either something to do with those two locomotive or the decoder or a physical interface issue between the locomotive chassie and the track.
Thanks so much for the update and glad that you are on your way to a solution. Your situation is typical, and it always takes time, back and forth, give and take, to nail down the problem. You did your own detective work which is great because you solve your problem and spare us a lot of speculation and random suggestions to reach the problem and find a solution.
Keep us posted. We will be interested in how a decoder has caused the problem.
I had a similar problem with both DC and DCC engines going through a turnout. My multimeter showed continuity throughout the problem area. I assumed it was the frog. It turns out that there was a bad solder joint around a rail joiner. The weight of a passing loco would depress the rail just enough to break the circuit but the multimeter probe would not.
update… ran into another issue the system would trip prior to the reverse operating… But I add a second turn on the current sensors for the reverse which lowers the milliamp leve for the reverser to trip… works great now.
