Automatic Reversing

[Mike Bett]

I am installing an analogue tram line separate to my main digital layout. I am using an Aristo-Craft 11091 automatic reversing unit with an old LGB 5000 power unit.
All has been wired as specified and the correct diodes have been used and soldered across the rail breaks, they are installed as directed with the stripes facing in the same direction.
I turn the power on and the tram goes merrily down the line over the diode and off the end of the track (have not installed the buffers yet). No stopping or reversing.
Any ideas?

 

[Neil Robinson]

I can think of four theoretical possibilities.
1/ The diode is the wrong way round, despite any instructions or markings reverse the diode and see if it makes any difference.
2/ The diode is faulty.
3/ The break in the rail bridged by the diode hasn't been cut through properly or there's a bit of metal bridging it.
4/ The track power has been fed at one end rather than the middle of the shuttle track.

Ah, I've just accessed the Aristo instructions online.

Their diagram appears to be intended for NMRA standard direction locos. If I'm right, as LGB set the large scale standard as the opposite direction, you will need to reverse the diodes

 

[Mike Bett]

Hi Neil,
Thanks for the reply.
3 and 4 are not the reason.
Regarding 1, do you mean reverse the direction of just one of the two diodes?
I have spare diodes so can try 2 if 1 will not solve the problem.
Mike.

 

[Neil Robinson]

Hi Neil,
Thanks for the reply.
3 and 4 are not the reason.
Regarding 1, do you mean reverse the direction of just one of the two diodes?
I have spare diodes so can try 2 if 1 will not solve the problem.
Mike.

Hi Mike,
I've just edited my earlier post. If I'm right you'll need to reverse both diodes but you can try one first and see if it works for that end.

 

[Mike Bett]

Thanks again - will work on it soonest and let you know the results.

 

[KeithT]

I also have an Aristo(Crest) reversing unit which does not work.
I didn't realise the diodes could be "wrong way" because when it reverses they become "right way". At the very least just changing the polarity of the feed would have the same effect. Or have I missed something obvious?

 

[chris m01]

I'm sure Neil is absolutely correct on this - as usual. Both diodes will need to be the other way round and it will work a treat.

 

[KeithT]

Hi Neil,
Thanks for the reply.
3 and 4 are not the reason.
Regarding 1, do you mean reverse the direction of just one of the two diodes?
I have spare diodes so can try 2 if 1 will not solve the problem.
Mike.

If the diodes are on a straight section of track just turn the lengths rather than re-solder.

 

[Neil Robinson]

Hi Neil,
Thanks for the reply.
3 and 4 are not the reason.
Regarding 1, do you mean reverse the direction of just one of the two diodes?
I have spare diodes so can try 2 if 1 will not solve the problem.
Mike.

If the diodes are on a straight section of track just turn the lengths rather than re-solder.

With respect Keith this may not work.
If I understand you correctly you will end up with the diode pointing the other way, but in the other rail, thereby cancelling out the effect.

 

[KeithT]

Hi Neil,
Thanks for the reply.
3 and 4 are not the reason.
Regarding 1, do you mean reverse the direction of just one of the two diodes?
I have spare diodes so can try 2 if 1 will not solve the problem.
Mike.

If the diodes are on a straight section of track just turn the lengths rather than re-solder.

With respect Keith this may not work.
If I understand you correctly you will end up with the diode pointing the other way, but in the other rail, thereby cancelling out the effect.

Hi Neil With my knowledge of electrics I am not surprised!!! But, I mean't turn both.
I think I will just rely on reversing the controller each time.8|

 

[Tony]

I am installing an analogue tram line separate to my main digital layout. I am using an Aristo-Craft 11091 automatic reversing unit with an old LGB 5000 power unit.
All has been wired as specified and the correct diodes have been used and soldered across the rail breaks, they are installed as directed with the stripes facing in the same direction.
I turn the power on and the tram goes merrily down the line over the diode and off the end of the track (have not installed the buffers yet). No stopping or reversing.
Any ideas?

Thats the problem they need to face in opposite directions
Tony

 

[Dtsteam]

they are installed as directed with the stripes facing in the same direction.

Thats the problem they need to face in opposite directions
Tony

Although its counter-intuitive, if the same rail is broken at both ends, then the diodes need to point in the same direction.
I found that one out when my box cab trundled of the track at the back of the shed, because I was too lazy to fit a buffer stop.

 

[tramcar trev]

Don't know if this is of any help. I'll try it out on my tramway as a preventative measure to stop rear enders etc....

http://www.gordonstrams.net/

 

[beavercreek]

I have used reversing units made by LGB (1amp capacity), Aristocraft (1.5 amp capacity) and ABC Electronics (8 amp capacity, bought from ebay). The diodes in all situations should be installed facing the same direction but when it seemed that a unit was defective, or not functioning correctly, I just brought the controller knob to zero and then turned it to the other direction OR in the case of Train Engineer, just reverse the direction of the running. This would always rectify any problems.
The diodes are pretty robust and should not cause problems (I have the original ones that were installed when using the 1 amp units, even now that I am using the 8 amp unit.
I moved onto the 8 amp unit as I have some serious inclines and wanted to run more powerful locos so 1 amp was not enough and caused the reversing units to 'pulse' as they overloaded. None of the units actually became defective themselves, even being left outside under cover or being overloaded as in the 1 and 1.5 amp variety

 

[CoggesRailway]

Don't test it with two locos unless you are sure that they have the same polarity. I set one up and this confuse the hell out of me!

 

[Tony]

I Think the statement has got lost in translation .....Some would read it ....The both the stripes facing north ,east, south or west.....some might read it as both facing towards one eg station that was a terminus..... where as both ends of the line need to me a mirror of each other

 

[Mike Bett]

Hi all,
The sun (what?) shone today so got out to fix the automatic tram reversing track.
Thanks for all the ideas, tried most of them.
All is working just fine now, I tried all diode configurations, the last I tried ( sods law ) worked nearly perfectly, just did not send the tram back the second time, so installed a new diode and bingo.
The final solution was the mirror image of the Aristo instructions.
Diode on the left end of track, bar on the right and diode on the right end of track, bar on the right. This works perfectly ( for me ) when the controller power is for forward motion.
Thanks again for all the help.
Mike.