Shorting track problem

[AndyThomas]

Hi everyone.

Dont know if anyone can offer any suggestions about a problem I have. I have quite a large layout (10 metres or so) and I have been running trains for several months with no real problems but then trains started going slower one way. Now they run fine one way but barely go the other way and now keep stopping. I did leave the transformer on for several days by mistake which is one of the older H & M twin controllers and thought I may have done some damage to it as it was quite hot . However I have swapped it for a spare one I have and its still the same so assume I may have a dodgy connection somewhere but cant see why its running fine one way and not the other. Any ideas about this ladies and gents.

Andy

[96RAF]

Possibly a point has gone duff. See FAQs for testing procedure.

Or if you have made track changes you may have introduced a reverse loop. Again see RL tutorial sticky.

[ColinB]

To me it sounds like a dodgy controller, but you have changed it. Are you sure the replacement is ok. It sounds like a diode effect, so have you anything attached to the rails that could cause that, things like lights or frog switching circuitry. I suppose the next thing is to check the voltage on the controller terminals where they connect to the rails and check you are getting the right voltage in forward and reverse.

[ModelerXYZ]

A few things to deal with this:

Clean the track. It may not sound like much, but it definately improves running.

Test to see if the problem is with all locos, or just if 1 is on the track.

Check the fishplates-If they work loose, (sometimes they do) they can cause poor running.

Hope this helps,

XYZ

[Yelrow]

Andy, hi, doubt if you have harmed H &M controller. They are built like tanks. I have several in regular use. They do get warm as a matter of course. If in doubt, have it tested by an electrician. Bon chance.

[rpjallan]

I agree with ModelerXYZ regarding fishplates. Sounds to me like poor connections. Do you only have one connection from your controller to your track?

[AndyThomas]

Hi there. No I have 2 feeds to the track and it was new fishplates and track all round when it was laid. Its the fact it runs fine one way and not the other that is bugging me and its the same on all trains. I have tried a third H & M controller now and its the same so must be a track problem. Wondering if a track pin is lying somewhere on a point. I will examine the layout again.

[AndyThomas]

Hi there. No I have 2 feeds to the track and it was new fishplates and track all round when it was laid. Its the fact it runs fine one way and not the other that is bugging me and its the same on all trains. I have tried a third H & M controller now and its the same so must be a track problem. Wondering if a track pin is lying somewhere on a point. I will examine the layout again.

What is the RL tutorial??

[Yelrow]

Do you have a Dapol track cleaning wagon. They have a built in Hoover. I have often found a foreign object by running mine. Very useful addition to a layout. Another way is to use a 12 volt meter, or one of those screwdrivers that light up. You can then check voltage each side of every point. Could well be a duff point, which this way will show up. Doubt its a fishplate.

[Brew Man]

If you had any shorts at all on the track, nothing would run at all in either direction. So it's a bit of a puzzler as to why everything runs fine one way but struggles the other. It draws one to thinking gradient, but you say the layout is flat. So....

[96RAF]

What is the RL tutorial??

 

 

Reverse loop - where a loco can leave a place on the layout and by way of track geometry come back to the same place but facing the other way - a reverse loop without special switching will cause a short - see this guide https://uk.hornby.com/community/forum/faq-do-i-need-a-reverse-loop-module-and-how-do-i-install-one-322539

 

 

[Brew Man]

Again, if an inadvertent RL had been laid, i.e. no IRJs in the reverse section, a permanent short would be created and nothing would run. I'm struggling to think what it might be.

[Topcat1707821625]

@AndyThomas

Have you tried disconnecting the controller completely, removing all rolling stock from the track and measuring the resistance between the tracks with a multimeter, in one direction then in the other? Obviously you should measure an open-circuit in both directions but if it measures open-circuit in one direction and zero or a low resistance in the other direction then the only thing I can think of, as previously mentioned, is that there is a semiconductor junction in there somewhere, e.g. a diode/rectifier.

If it does measure open-circuit in both directions then maybe there is a problem with the loco. I have had problems with tender-drive locos that would run in one direction but stall in the reverse direction because of worn teeth in the gear train.

[96RAF]

Maybe post a picture of the track plan in case there is an obvious oops in there.

[rpjallan]

There has to be some kind of high resistance in a connection somewhere. Just because all the track and fishplates were new when it was laid doesn't mean a bit of corrosion or something hasn't crept in somewhere. How are your wires from your controller connected to the track?

[Topcat1707821625]

@AndyThomas

If the problem was simply a high resistance connection it would surely affect operation of the loco in both directions. Have you tried reversing the connections from the controller to see if the effect reverses?

Just to be clear, does the problem occur when the loco reverses or when you turn the loco around and send it along the track the other way? Have you tried more than one loco?

[AndyThomas]

Thanks for all the advice. This has "sort of sorted" itself but not sure what the actual problem was or still may be. I have removed the secondary wires from the controller and just left one pair of wires connected to the rails. I know that everything was working fine for several months so all the wires were originally in the right place. I think there is a strong possibility that one of my two grandsons has pulled a wire from somewhere when I wasnt around and their mom has randomly put it back where she thought it came from. There was definately a short as I could see a spark coming off a connector a couple of times when running in the problem direction. I will put the wires back in place one at a time and see what happens.

Thanks guys and gals

[96RAF]

Sounds likely Andy. I guess the only safe way is to disconnect all link wires and reconnect ensuring correct polarity. You could make use of a choc-block terminal strip to secure all your feeders into one place then run a single feeder pair back to the controller. That might preclude little fingers messing things up again.

You are likely already aware that if using more than one controller (or channel) that you need to isolate sections under their control from the other sections, else when you swap directions on one controller (channel) you make a short circuit.