Staging yards control Part II …

Hi all,

Quickly following on from Part One, I will attempt to describe the wiring that I have done.

Probably the first bit of wiring I did was when I was installing the Cobalt motors.  The turnout vee crossings will be ‘live’ and polarity switched when the turnout is thrown.  This is done using the auxiliary contacts within the motor.  So, positive and negative droppers were connected to the turnout at an appropriate spot and along with the dropper from the crossing, were terminated at the motor.

turnout motor wiring

Wire size is 7/0.16mm, Altronics Light Duty Hook Up Wire, Cat No. W2250 (Red), W2251 (Black) and W2255 (Green).  I bought 100 metre rolls of ten different colours years ago.  The grey wires are figure 8 type that supply power to the motor.

As mentioned above, the red and black droppers are connected to a convenient spot on the turnout.dropper connections for vee crossing polarity

With the requirement for each road to be a detection section, I had to run a positive bus wire for each road, including the turnout ladders at each end of the yards.  There a total of twenty two detection sections, eleven per yard.  Once these bus wires (1.5mm2) were run, smaller gauge dropper wires were attached to every piece of rail and then connected to their respective bus wires.  The negatives from each road were bonded together and connected to a negative bus for each yard.  The photo below shows a section underneath the UP yard showing the bus runs, the positive rail connections and the common negative connections.

detector section bus wiring

dropper connection to positive rail

The wiring for each turnout motors was run using figure 8 type wire back to a central terminal block, one for each bank of eight motors.  To connect these back to the control boards (SMD-8’s), four core alarm cable was used.  This was obtained from my local electrical wholesaler.  I got one hundred metres for only thirty five cents per metre.  I needed four runs of this cable for each bank of turnouts.  The conductor size of this cable was 14/0.2mm.

turnout motor wiring

Due to the small conductor size of the alarm cable and figure 8, and the large terminal block connections, small ferrules were used to make it easier to terminate these wires.  The ferrules were obtained from the local Jaycar store, part number PT4433.

All this wiring had to be terminated at the control boards.  I chose a location under one end of the UP yard and screwed some timber to the wall to make a mounting board.  The image below shows the finished product.

staging yard control

The following images show close-up views of the individual components.

SMD-8 and FOB-C boards for turnout control

There a four SMD-8 boards that control the thirty two point motors.  The alarm cable wiring from each bank of eight is terminated at the fan-out board (FOB-C).

BOD-8 boards for train detection

There are three BOD-8 boards for the detector sections.  The Cat5 wiring comes from the current transformers.

CT's for current detection of trains

There is a total of twenty four detection sections, twenty two for the yards and another two for the sections between the UP yard and Kankool and the Down yard and Pangela.  At the moment, I haven’t installed the last two CT’s, but the Cat5 wiring is terminated already.

Relays for road power control

The wiring to control the power to each road was probably the most complex.  The original plan was to just use the RB-4’s, but I found it was too difficult to terminate the larger wires (brown & grey) into the small terminal blocks on the RB-4.  So I purchased another lot of relays that would control the main DCC power and used the RB-4’s to control these new relays.  I was then able to use much smaller hook-up wire in the RB-4 terminals.  The new relays were from Altronics, part number S4197 for the relay and S4320 for the base.  They are mounted on DIN rail which was also obtained from Altronics.

TC-64 Tower Controllers

All the boards are connected to the two TC-64 Tower Controllers by 10-way ribbon cable.  The TC-64’s are connected together via 6-way flat data cable with RJ-12 type connectors.  These are then connected to the Locobuffer USB interface, which will then be connected to a laptop that will sit just to the right hand side of the control board on a shelf.

I am yet to test the system as it will involve a lot of time to carry out the programming and addressing of the hardware in JMRI and PanelPro.

For those interested, I have included some wiring and schematic diagrams that I drew up to not only assist in the actual wiring installation but to help with future fault finding.





Posted on May 5, 2013, in Electrical, Trackwork and tagged , , , , , , , , , , . Bookmark the permalink. 8 Comments.

  1. Hi Ian,

    A very impressive project and thanks for providing such clear information in your blogs.

    I’m in the initial stages of a similar project and note that you have used many of the electronic components I’m planning to use. I have one query regarding DCC bus power to turnouts and wonder if you might be able to help.

    I will be using Cobalts and the RR Cirkits SMD-8 to drive them just as you do. Will I need to provide bus power to the turnout as well as the three cables from the Cobalt (to the frog and +ve and -ve tracks) as I assume the DCC is being provided to the Cobalts from the turnouts for them to return the required frog polarity via your green lead?

    Many thanks

    • Hi Anthony,

      You are correct in your question. The turnout (apart from the frog) is connected to the DCC bus as it normally would be for plain track. The wires from the Cobalt to the frog are purely to allow the Cobalt to change the polarity of the frog. The red and black tap off the DCC bus, because the power to the frog must come from the same source ie the DCC bus.

      I hope that answers your question.

  2. Quite impressed by the neatness of your wiring.

    • Hi Alan,

      I am an electrician by trade and have always taken pride in my work. The layout is no different. It also helps with fault finding if the need ever arises.

      I am also enjoying following your progress on the LK&O.


  3. Hi Ian,

    I’ve done plenty of layout wiring so I can really appreciate the effort gone into planning, such neat installation and thorough documentation.

    Looking forward to reading about your experiences with JMRI and automation.



    • Hi Martin,

      There certainly was a lot of planning that went into the project, which probably doesn’t get reflected in the blog posts.


  4. Ian Phemister

    Wow! Very impressive. Looking forward to seeing it all work. Nice neat job of the wiring. Who said only two wires are needed for DCC.

    • Ian,

      Thanks mate. I’m also very much looking forward to seeing it all work. I’d already played around a little bit with PanelPro and got some of the stuff working, albeit in simulator mode, and it was pretty cool.


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: