Lionel locomotive shorts at terminal track

@Pilot2fly posted:

Hi everyone,

I just replaced the front drive axle due to the old one being bent on my Lionel Southern Crescent 38607 locomotive. It runs like a champ now.

Problem is, as soon as it goes around my loop and makes it to the terminal track, it completely stops every time and won't move again unless I pick it up and place it somewhere else. It also trips the Z1000 circuit breaker when it does this.

Layout wiring is correct, and this doesn't happen on my other locos.

I attached a photo of where it stops each time.

Hi Pilot2fly, that's a puzzler, very unusual behavior.

1) Has anything changed with any track or accessory wiring since you started working on the 38607?

2) Do any other Locos stop at the terminal track and/or trip the Z1000 breaker?

If the answer to both questions is no, posting some close-up pictures of the terminal track section without the loco there and another pic of the underside of the 38607 may be helpful.

3) Do you have access to a multi-meter?

Thinking of possible things that may cause this.  Is your 38607 heavier than your other engines?

Have you tried running it in the other direction ?

there is a small slit in the wiring where the wire comes out the the terminal track, the weight of the engine is causing the short.  remove the engine and push on the track, it should short.

Yes it's quite heavy, but when I press on the terminal track it doesn't short. I adjusted the screw for the front two wheels and that fixed it.

However, now it won't go past a turnout without stopping. This leads me to believe one of the rollers isn't working. I noticed that I had two different sized screws holding the rollers in. They both screw in, but ones longer than the other.

I took the rollers off to inspect and screwed them back in. Now the train gets no power at all and flips the transformer when I try to give it power.

Only happens on this locomotive. All my other locos work fine and navigate the turnouts quite well.

I think I'm going to take it to my local model train shop after work Friday and see if they can look at it. I'm fairly new to all this, and changing the front drive axle had me cursing like a sailor.

A friend of mine had the same problem.  It ended up being the rivet on which the front truck spring is attached was too long and hitting the center rail.  Look for something that could be shorting out by hitting the center rail.

Ron

Thanks, I'll set it on the track this afternoon and see if I can use my phone to look under the train and see if anything is touching the rail.

I also just remembered that last night I was screwing in a screw next to the rear drive wheel (for the middle plate) and could only get it half way because I stripped the head. I wonder if that screw might be touching a rail.

@Pilot2fly posted:

Thanks, I'll set it on the track this afternoon and see if I can use my phone to look under the train and see if anything is touching the rail.

I also just remembered that last night I was screwing in a screw next to the rear drive wheel (for the middle plate) and could only get it half way because I stripped the head. I wonder if that screw might be touching a rail.

If it is that screw, it will have little pit marks on it from shorting the center rail.

Maybe it's my eyes or the angle of the pics, but it looks like the rollers are slightly crooked; some rods are bent; and the traction tire wheelset looks to be crooked.

I think any of those or the combination of all three might be causing the loco to short, especially on switches.

If you're concerned about the rollers, polish them with a Dremel and mild abrasive pad; then apply some contact cleaner; and finally lube lightly with an electronically conductive lube, like Bachman's. 

So after thorough testing, I can confirm nothing is touching the rails except the wheels and the rollers. I tightened up all the rods and screws. When I give it throttle on my Z1000, the loco doesn't light up and it makes a humming electrical sound. If I go more than half throttle it pops the circuit breaker. I think I've exhausted all my options for what I'm capable of. I spoke to my local model train shop and I plan to take it in Friday for repair.

Also of note, I did see some sparks Monday afternoon under the wheels when it was still running and smelled a burnt electrical smell. I'm guessing this has something to do with my issues.

Now you have brought up a new issue.  My own experience with sparks coming from the wheels was a pinched wire (thank you GRJ).  This shorted out the engine and tripped the breaker.  If nothing is touching the rails, take the shell off and look for a wire shorting out someplace.

Ron

If there is a pinched or loose wire, I'd speculate that it's most likely connecting the hot side (center rail pick-up roller) to the motor and is now shorting to the frame.  Best case, that burnt smell is likely melted wire insulation and would need to be repaired/replaced.

Opened up the shell. I don't see any pinched wires or scorch marks. Everything is connected. I did see a black wire that was tight but after loosening it, made no difference. Loco still hums when giving the track power and flips the circuit breaker on my Z1000.

Can you guys look and see if I'm missing something? Disregard the popped out black arm in the first photo. I fixed that before testing the loco.

Nothing obvious to me in pics at issue.  But I would ask you to look closely at a couple of things noted in pic by red arrows:

1) the bulb socket to see if there's anything in there causing a short, it seems there's some black substance on the outside of it.

2 ) where the black wire passes through the smoke stack bracket to see if wire insulation is damaged

A couple of additional suggestions if the above check out:

If the smoke switch is on, try turning it off

Re-install wheel linkages and then try running the loco without it's shell installed.

Would also suggest when testing above, preferably in low ambient lighting, to look for any sparks inside the loco.

Thanks Steve and everyone else who has helped me so far. I truly appreciate it!

I tested the loco w the shell off. Turned smoke switch off, reinstalled linkages. Not seeing any sparks, but I still hear the hum when I give the track power. I still have to check the front bulb.

I found that part of the wire insulation for the small rear wheels is damaged near the soldered point inside the loco and a small amount of the inner wire is protruding and looks to be cut. I will try to cut that part out and resolder to see if that helps. I did have the rear wheels off quite a bit when replacing the front drive axle, so maybe with all the movement and strain on the wire it could have caused that.

Even though this engine was mostly running fine at one point, just out of curiosity  (following a tip from @gunrunnerjohn in another thread) does the flywheel turn by hand freely through a full rotation of the wheels?

Hi Steve,

Yes the flywheel turns freely both directions and wheels respond correctly thru a cycle.

I just did another test and found something I didn't see before. When I give the locomotive power, the rear roller gets VERY hot. This is only from about 5 seconds of power, then it trips the  breaker.

Edit: can't find a cause for the hot roller. Appreciate all you guys' help. Its given me alot of insight into model train maintenance and I'll be able to easier explain to my model train shop the issues. I'll let you know what happens Sarurday once they repair it.

Took locomotive to the train shop, they looked at it and tested. One of the screws for the rollers was the incorrect one and was causing a short. We solved that issue, but there's also arching on the right wheels of the loco. They believe there may be a missing spacer or insulator. I'm also missing some screws to hold down the metal plate. And now I know I'm missing a screw for the roller since one was incorrect. I ordered the missing screws from Lionel.

I decided to take the loco home and try to find what's causing the arching on the right side of the loco. Below photos don't show anything obvious to me.