Control issues in a fiddle yard

[Guest Jack Benson]

This is our fiddleyard. The turnouts on the right are isolated from those of the left by insulated rail joiners on every rail. There are two feeds, one at each end of the fiddleyard and each turnout has a separate switch for the Vee supplied by feeds from individual stock rails. All turnouts are Peco small radius. The fiddleyard is now hidden (ish) by a very permenant backscene and the underside of the layout occupied by a number of storage units.

 

 

As originally built, the layout was DCC but individual turnouts were not isolated at their exits, merely a separate switch for the Vee supplied by feeds from individual stock rails. Testing was simply completed by running a loco around the layout with no other locos available for testing however each siding was tested by running the loco through the fiddleyard.

 

Following the death of one of the leading (the electrician) members of the group, the layout was temporarily abandoned, all his DCC equipment removed and the sold. The layout was then intended to be run as DC fed by just one handheld controller with the self-isolating Peco turnouts providing the necessary control of trains.

 

It was not run until two weeks ago when a pre-festive running session (three of us socially distanced) and we attempted to run all our stock.....except some of the sidings in the fiddleyard appeared to be constantly live, even more bizarre was the sight of two trains running in opposite directions!

 

Our first reaction was that the wiring was only suitable for DCC and that we should acquire yet another set of equipment but this response does not explain reversed polarity in the fiddleyard sidings......another suggection was that fan sidings tend to suffer from 'backfeeds' and that a simple fix is to cut through the rails at the left side and install a panel of six individual on/off switches.

 

Before we abandon our project yet again and take up yoga for pensioners, does anyone have a clue as to what we did wrong?

 

Cheers and Stay Safe, 2021 must be better.

 

 

 

 

[Butler Henderson]

Would suggest their might be further isolated sections with separate feeds to them. The scenario you describe of locos moving in opposite directions arises from current passing from a voltage fed rail through a motor to a rail that is nominally dead but is someone how connected to via more locos to the other track feed.

[dasatcopthorne]

Sounds to me that there must be feeds to the actual sidings and that one or more of these feeds is reversed. The two outer most tracks should work fine as one rail of each has no switched frog and fed direct from the main circuit.

 

I am guessing the the track with reverse polarity is one that is reached via at lease two frogs. The feeds to these track could be reversed as on DCC it would matter as the supply is AC.

 

Best of luck

 

Dave

 

 

 

[Guest Jack Benson]

Hi,

 

There are just two feeds, one at end end of the fiddleyard. The fan of turnouts on the right are isolated from those of the left by isolating rail joiners on every rail.

 

Thank you

 

 

[Butler Henderson]

There must be something else, as you say it was intended to be DCC and it is normal DCC practice to have all tracks live. 

[Ron Ron Ron]

Check to see if there’s any linking wires, or jumper wires between each of the sidings, put there simply to help make the constant DCC supply more robust.

Such connections wouldn’t necessarily need to be connected to the main track feeds.

Edited December 26, 2020 by Ron Ron Ron

[Guest Jack Benson]

Hi B-H,

 

I need to wait until I have access to the wiring and someone can help do continuity checks (we are Tier 2 and the other members are in Tier 4) and as a just-in-case fallback, I just bought another DCC set-up. It is OK, we have been waiting for a few years to run the layout, another couple of months isn't going to hurt........

 

So much fun

 

Cheers and Stay Safe

 

 

[dasatcopthorne]

5 hours ago, Jack Benson said:

Hi,

 

There are just two feeds, one at end end of the fiddleyard. The fan of turnouts on the right are isolated from those of the left by isolating rail joiners on every rail.

 

Thank you

 

 

 

Thinking of the two 'centre' sidings, if there are only two feeds at each end, how are they powered?

 

The rails of both these two sidings pass through frogs that you say have insulated joiners on each rail.

 

Dave.

[Butler Henderson]

3 hours ago, Jack Benson said:

Hi B-H,

 I just bought another DCC set-up. It is OK, we have been waiting for a few years to run the layout, another couple of months isn't going to hurt........

Struggling to understand how it ever worked on DCC with the description of trains moving as you describe; could be whoever was wiring it had it working by switching the points like you say you expected it to work and then decided to link rails together to make them live and has got some connections mixed up. A DCC wired layout should work on DC, albeit usually with a lack of isolating sections.

[ikcdab]

It's difficult for anyone to give a precise answer without seeing the actual wiring and section breaks. 

My own fiddle yard is exactly the same layout and I have a complete break through every rail near one end.

I think you need to inspect the wiring and draw it out exactly with the rail breaks and then we might be able to help.

[DCB]

If you can get at the top of the layout Just chop the rails and fit insulated joiners against all the rails leaving the points for the loops, frogs and stock rails and feed both rails of the the loops from the controller or left side and right side of the layout by double pole switches.   Trains running backwards while other go forwards simultaneously when usually both go the same way is a sure sign of back feeds and that is a nightmare.  I had it and had to completely re wire my loco sidings to solve it.

[Guest Jack Benson]

David,

 

Oddly enough, that is our plan if we cannot find the cause of the problem.
 

One nagging doubt, each turnout has a separate switch for the crossing Vee but if the two jumper wires under each of the Peco turnouts had not been removed, would this simple mistake be responsible for the problem?
 

Cheers

 

 

[DCB]

4 hours ago, Jack Benson said:

David,

 

Oddly enough, that is our plan if we cannot find the cause of the problem.
 

One nagging doubt, each turnout has a separate switch for the crossing Vee but if the two jumper wires under each of the Peco turnouts had not been removed, would this simple mistake be responsible for the problem?
 

Cheers

 

 

The way to check it is to disconnect the switches, easy if they have screw contacts.  not so easy if they are soldered.    I use DC and outside I double up frog feeds with standard electrofrog  frog wiring from the point blades and an additional microswitch on the tie bar, in parallel with it. It works fine 98% of the time.

Is it common return?   That is where 97% of my problems originate.

Does one test loco run through all the roads and stop when the points are against it?  If so does the loco stay motionless on every road with the points against it while another loco runs through every other road? 

Write down which combinations work and don't work to give a baseline, it could be as simple as a switch not throwing  internally.   I have had three locos side by side and one goes left to right and the other two right to left when only one should move, It needed a complete redesign, but only a few wires changed.   Rogue unexpected current paths depending on points settings are the real joy,     Have fun. Its good to have a project with lock down etc.

[Guest Jack Benson]

As a postscript, it was suspected that the fiddleyard had been originally wired for DCC but worked with just one loco was used with a DC controller. 
 

A second hand MultiMaus system has been connected and everything is fine, problem solved except we now have to ‘chip’ nine locos but a lot easier than removing the scenery to access the track and wiring.

 

 

Thank you