# tender runs, but engine is dead



## marty9930 (Dec 29, 2015)

Good evening!


I have a bit of an anomaly here…
I just recently had a 4-4-0 serviced and cleaned with a statement from the technician that the engine runs strong and to check my tracks. Thing is, the tracks ARE clean, and I seem to have the same problem on a completely different set up. I have two other test locomotives and they work fine on both sets of tracks.


What’s happening is this: when the tender is on the tracks, the engine runs very well. The minute the engine rests on the rails, I get nothing. Does this sound like something familiar?

Tracks are in great shape and not dirty, all wheels are in even contact with the rails. Locomotive is HO scale.


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## MtRR75 (Nov 27, 2013)

Some locos pick up the power from BOTH locomotive drivers AND tender wheels. It sounds like this might be the case. Usually one tender truck picks up power from the right side of the track, and the other truck picks up power from the left side of the track.

It is important that the right-side loco pick-up wheels and the right-side tender pick-up wheels are both connected to the same side of the motor. And both of the left side pick-up wheels need to be connected to the other side of the motor. If the wheels on the tender were removed and reinserted backwards, then you would have a short when the loco and tender pick up power different sides of the track and deliver it to the same side of the motor.

If you have a multimeter, you can test the resistance between the tender wheels and the axils to determine which wheel is electronically connected to the axil. You can also remove the loco and tender from the track and test the connection between the tender and loco pick-up wheels to see which are connected to which, electronically.

If this does not resolve the issue, you might have to remove the shells from the loco and the tender to follow the wires to make sure that everything is hooked up correctly.


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## Cycleops (Dec 6, 2014)

If you've just had the loco serviced and it runs strongly i would have thought that eliminates that but you say when the engine goes on nothing. So the pick ups in the tender are working and picking up both tracks. It could be a short within the pick ups in the loco. Remove the body and see if you can find some wires which might have come off or are shorting somewhere.


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## DonR (Oct 18, 2012)

Mtrr75 and Cycleops are right on. There appears
to be a short circuit between the tender wheels and 
the loco wheels.

You did not say, though, that your power pack 
indicated a short circuit when you placed the loco on
the track. Is that, in fact, the case? If so,
follow the tests Mtrr75 suggested.

Don


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## marty9930 (Dec 29, 2015)

I'll rotate one of the trucks on the tender and see what happens. Thanks!


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## marty9930 (Dec 29, 2015)

Thanks for the reply. I was certain the only things in the loco were drive and headlight necessities. I'll open that up too and see what's in it.


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## marty9930 (Dec 29, 2015)

DonR said:


> Mtrr75 and Cycleops are right on. There appears
> to be a short circuit between the tender wheels and
> the loco wheels.
> 
> ...


Thanks, Don. The power pack does indicate a short circuit, but it is very inconsistent, only occurring on occasion with the 4-4-0 in question. And again, the other test locomotives seem to operate without trouble.


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## MtRR75 (Nov 27, 2013)

Intermittent short circuit. OK. Next question, is there a pattern to the intermittent short circuit? Does it always happen in the same place? If so, then there is likely a track problem. But since the other locos work fine, it must be some interaction of that loco with those specific sections of track.

If the short circuit happens in different places every time, then it is likely a locomotive problem.  If this is the case, it is time to open up the loco and the tender and trace all of the wires. Make sure that all of the solder connections are solid and not loose. Make sure that no stray strands of wire are sticking out from a solder point -- where they could contact something to short out the loco. If there is an electrical plug that connects the loco to the tender, check it to make sure that no pins are bent.

P.S. I reread your post. By "inconsistent" do you mean that the short sometimes happens and sometimes does not happen with the loco in question? If so, what I just wrote applies. Or do you mean that the short always happens with the loco in question, but never with any other loco? If so, then ignore what I just wrote and go back to my previous post and follow those suggestions.


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## DonR (Oct 18, 2012)

Have you checked that the tender wheels are turned correctly
as suggested in Mtrr75's #2 post?

Place both the loco and tender, still connected to each other on their sides.

Set your multi meter to ohms.

Put one probe on the Right front Loco wheel. Touch the other
wheels one by one the Right side of both loco and tender. You should
get the same reading at each one. Then do the same on the Left
side wheels with one probe on the left front loco wheel and
the other touching each of the other left side wheels.
If you get the same readings touching all wheels it would
indicate that the problem is not turned tender wheels.

However, if you get the same readings on the loco wheels and ONE
tender truck, but a different reading on the other tender truck
the indication would be that the one with the different reading
is turnout around. This could cause a short.

If you get a different reading on both tender trucks both are
turned wrong. This could cause a short.

Don


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## thedoc (Oct 15, 2015)

Were the Loco drivers installed correctly? When you say "nothing" do you mean nothing as opposed to shorting out, there is a difference.


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## marty9930 (Dec 29, 2015)

DonR said:


> Mtrr75 and Cycleops are right on. There appears
> to be a short circuit between the tender wheels and
> the loco wheels.
> 
> ...





MtRR75 said:


> Intermittent short circuit. OK. Next question, is there a pattern to the intermittent short circuit? Does it always happen in the same place? If so, then there is likely a track problem. But since the other locos work fine, it must be some interaction of that loco with those specific sections of track.
> 
> If the short circuit happens in different places every time, then it is likely a locomotive problem. If this is the case, it is time to open up the loco and the tender and trace all of the wires. Make sure that all of the solder connections are solid and not loose. Make sure that no stray strands of wire are sticking out from a solder point -- where they could contact something to short out the loco. If there is an electrical plug that connects the loco to the tender, check it to make sure that no pins are bent.
> 
> P.S. I reread your post. By "inconsistent" do you mean that the short sometimes happens and sometimes does not happen with the loco in question? If so, what I just wrote applies. Or do you mean that the short always happens with the loco in question, but never with any other loco? If so, then ignore what I just wrote and go back to my previous post and follow those suggestions.


To clarify MtRR75, I mean that the loco in question sometimes shorts and sometimes does not. IT is difficult to say whether it is happening on any specific points on the track as the loco will not move. And again, the other locos I use don't have a problem. Thanks! And to DonR, when the short does occur, the loco is on the track.


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