DCC BLI Reading T1 causes short on track and stops


O

Orange Irish

Member
Other locos work just fine all around the track, but this one causes a short and stops after a few inches of travel no matter where I place it on the track. Standing idle the sounds work fine, but moving is the problem. It's clean and not used much to this point, and I can't see any obvious signs of a problem. It worked before on a previous version of my layout before a re-model, but was packed away for a time. What would be the most likely causes for me to check into?
 
People consider a "short" to be several things. Does the engine just stop? Does a breaker trip on the layout?
 
The loco stops and at the same time the booster trips and stops power to the track.

And now, after running all locos last night (two at a time during several different sessions), I had a short caused by a minor derailment and a 2nd loco now will not run or make sounds, but the headlight works. Are the decoders in BLI Paragon 2s susceptible to damage or fickleness??
 
Orange Irish said:
The loco stops and at the same time the booster trips and stops power to the track.

And now, after running all locos last night (two at a time during several different sessions), I had a short caused by a minor derailment and a 2nd loco now will not run or make sounds, but the headlight works. Are the decoders in BLI Paragon 2s susceptible to damage or fickleness??
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They can be "touchy". You may need to reset the one that won't run, but first try setting cv19 to 0, and try again. Sometimes a DCC system will put an address in a phantom consist when there is a short.
 
For the 2nd problem loco, I first tried to pry the shell off the PRR M1 tender, and that was futile. I had to put so much pressure, without getting it off, that I knew it would break if I kept trying. It really was unbelievable how difficult it was, and now I'm afraid of having to try again down the road. So I eventually reset the CV to the default settings on the decoder. That worked and the loco runs fine now. Thanks!

The 1st problem loco still shorts out the track but I don't know why. I couldn't see any clear metal-on-metal issues going on...maybe a electrical pick-up is touching something it shouldn't underneath...
 
Orange Irish said:
For the 2nd problem loco, I first tried to pry the shell off the PRR M1 tender, and that was futile. I had to put so much pressure, without getting it off, that I knew it would break if I kept trying. It really was unbelievable how difficult it was, and now I'm afraid of having to try again down the road. So I eventually reset the CV to the default settings on the decoder. That worked and the loco runs fine now. Thanks!

The 1st problem loco still shorts out the track but I don't know why. I couldn't see any clear metal-on-metal issues going on...maybe a electrical pick-up is touching something it shouldn't underneath...
Click to expand...
I have a BLI steam engine that will short on a curve. The metal wheels on the pilot truck will touch the metal frame on a couple of curves on my layout. I had the choice of modifying the layout, or replacing the wheels with non-conductive ones. In the end, I repositioned the tracks to keep it from happening.
 
Repositioning tracks may not always be an option, and I prefer to find things that short on curves on the individual locomotive, difficult though that may be. If it does turn out to be metal lead or trailing truck wheels shorting against the frame, changing to plastic wheels may be your only option. My Mantua steamers all have plastic wheels on the pony and trailing trucks. But they came that way, so it was easy.
 
turn the lights off, watch the engine at a very slow speed for little flashes of light.

I have a brass N&W Z1a 2-6-6-2 and it only shorted on a curve, tough to find but I found one siderod was touching a drive tire, a tiny washer on the driver solved it.

I have had pilot wheels touching a frame or body part on some engines shorting, I grind off some interior body metal to make movement space, didnt bother exterior views at all. You will have to study over the engine carefully looking at wheels touching things or possible contacts bent touching something or anything.
 
dinwitty said:
I have a brass N&W Z1a 2-6-6-2 and it only shorted on a curve, tough to find but I found one siderod was touching a drive tire, a tiny washer on the driver solved it.
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Since this started happening after it was packed away, this would be my guess. Part of the drive rod, side rod, or other valve gear has been slightly bent and is now touching a drive tire. If you can find the spot, sometimes clear finger nail polish on the back side will resolve that issue.
 
dinwitty said:
turn the lights off, watch the engine at a very slow speed for little flashes of light.

I have a brass N&W Z1a 2-6-6-2 and it only shorted on a curve, tough to find but I found one siderod was touching a drive tire, a tiny washer on the driver solved it.

I have had pilot wheels touching a frame or body part on some engines shorting, I grind off some interior body metal to make movement space, didnt bother exterior views at all. You will have to study over the engine carefully looking at wheels touching things or possible contacts bent touching something or anything.
Click to expand...

This weekend I will have time to look. Thanks for the tip and I'll let you know.
 
Iron Horseman said:
Since this started happening after it was packed away, this would be my guess. Part of the drive rod, side rod, or other valve gear has been slightly bent and is now touching a drive tire. If you can find the spot, sometimes clear finger nail polish on the back side will resolve that issue.
Click to expand...

Yes good thought...thanks.
 
Well, I now see that the loco causes a short when the body gets rotated over the wheels counter-clockwise (when looking down on it from above). None of the rods or valve gears are bent, and the drive wheels are covered by plastic pieces that mimic the outside body of the wheels, except for the exposed ends of the axles. I laid the loco on it's side and observed that the rods might be touching the axle ends on the front one or two wheels. I dabbed epoxy on those metal ends, but that didn't work. The picture below is the loco I have. The front and rear trucks don't touch anything else, so I'm pretty sure it involves the drive wheels. As long as the various rods touch each other or connect to plastic they should work properly, correct?

Reading%20t-1%204-8-4.jpg
 
Does the locomotive pick up from the righthand rail only, with the left rail being picked up by the tender? If so, the left side drivers should be insulated from the frame. If the center of the left side drivers are metal, it is possible they may be touching and shorting against the frame on the lefthand curve. It might be necessary to remove the drivers and paint the inside with clear nail polish or lacquer. A way to test without disassembling the drivers would be to place the loco on straight track, run it slowly and press the front driver(s) against the frame. If the short occurs, that's you answer.
 
I think I can see the problem. The front truck will pivot to the point the inside edge of the metal wheels will touch the metal frame. If the frame happens to have current from the other side applied to it t that time, you will get a short. I currently have an I1 that does this, and the suggested fix was a pair of plastic wheels painted silver.
 
This loco picks up on all drive wheels, but not the leading or trailing truck. I've confirmed that the truck wheels are not touching metal...the inside frame is actually plastic. If I push on the drive wheels as it's moving nothing happens, but when I rotate the loco to the left, the two left front drive wheels get pressed inward (the two right front get pressed outward), and this is when the short occurs. I previously saw a spark behind the rear drive wheel and smelled an electrical odor there, but I'm not sure the short happens there or that's just where I get a visual cue. The inside of the drive wheels appear to just press against the plastic frame (maybe it's metal covered by plastic, idk). I can't see any metal parts poking out that could touch the inside of the drive wheels. I'm starting to think it's gremlins...or aliens.
 
If you've seen a spark there's definitely metal to metal contact and current passing across the contact.
 
With the nail polish solution, besides the inside of the side rods, is it bad to coat the outer perimeter of the drive wheels? Without knowing exactly where the contact is I might coat each one. If that will leave a terrible, over-shiny look can I use black paint and get the same effect?
 
You said you could smell the burn from the spark. Maybe use a magnifying glass and a small torch and see if you can pinpoint the contact spot. There may be a small flash affected area visible. If it's on the frame behind the wheel, that will confirm if the frame's metal or plastic. Paint could have a slight whitish brown area. Try the twisting test again in the semi-dark, while observing, if it sparks it might enable you to localise it easier.
 
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