Fiddle Yard Power

As the Aus7 ExpO draws closer the number of decisions I make about Morpeth that have some significance seem to grow exponentially. The oil siding, the new module, the pier siding and wiring these up all pose a series of decisions I need to make and commitments that will have to be lived with. As they all seem to pile in on one another it’s little wonder that I sometimes look back on layouts I’ve built and think, “why did I do it that way?”

This last weekend I had reached a stage where I needed to make a decision about the way power would be fed to the fiddleyard storage roads. There were a few simple of criteria for the method I settled on and they were:

1. I didn’t need every storage track powered at the same time, only the track that was aligned with the mainline on the layout needed to be “in steam”.

2. Whatever method I settled on to power the track needed to incorporate within it the ability to align the rails accurately across the turntable gap and lock these in place.

3. The system needed to be robust and extremely simple to operate so that a guest operator could understand very quickly how it worked.

4. The system had to be self-contained: I like to keep the number of separate parts to a minimum to simplify storage and transport. I wanted to minimise or eliminate the use of loose parts like bolts, clips, wands or cassettes that can go missing, rendering the whole system inoperable if I forget to pack something vital before an exhibition.

I visited the home of Brisbane modeller Rob over the weekend who has constructed a similar train turntable to mine. While this is used on an OO layout, the concept is exactly the same: a train exits the scenic portion of the layout and is staged on one of a number of storage tracks. The entire train can be turned without handling so that it can be run back onto the layout without touching it. Layouts that are configured in a fiddleyard to terminus arrangement need a quick and convenient way to restage trains once they exit the layout and, after having tried a couple of different methods, I feel that a train turntable is the best possible solution to getting trains back onto the layout.

The weakness with this method of turning trains is common to any turntable arrangement: how do you supply power to the tracks on the turntable? As my train turntable doesn’t require power to be supplied continuously to the tracks while the table is being turned this simplifies things considerably. The best method of supplying electricity to trains on the turntable is one where the power is delivered with a physical connection while at the same time the rails are aligned. Rob had solved this problem by the simple expedient of soldered pieces of brass tube that were electrically connected to each rail on the table which were then connected to the main layout supply by simple home-made bolts. When the tracks were approximately lined up these bolts were slid home, thus providing power to each rail on the table while the track was held in correct alignment. I will illustrate my version of this with a photo and what I’m describing will be a bit clearer.

As I drove home from Rob’s on Saturday afternoon I decided that I was going to use the same method he’d employed on his OO layout to deliver power to the fiddle yard tracks but with my own modifications. One thing I took home from the layout visit that was new for me was the use of square tube as the alignment method. I had never even considered this but I could see that soldering square tube to a base would offer far greater strength that using round tube due to the larger surface area available on the mating surfaces. This is important as this method of power delivery would also be used to hold the table in place and the extra grip provided by the square tube wouldn’t go astray.

I also decided that I wanted to simplify the delivery of track power across the baseboard joint between the scenic portion of the layout and the fiddleyard. I had all the hardware to deliver power via my usual method of eight pin DIN plugs and sockets however it suddenly occurred to me that a far simpler way of crossing the layout gap would be to run the power through the Station Road Baseboard alignment dowels I use to hold the modules in alignment. These are lovely brass turnings and I decided that they would be perfect way to simply deliver DCC track power automatically as the male and female halves were brought together each time the layout was erected. Item 4 on my list of criteria said reduce the number of extraneous parts. Done deal! 🙂

On Rob’s layout he had soldered the ends of his rails to a large section of paxolin copper clad material. I find that this isn’t necessary with 32mm gauge track as a method of holding track in position so I stuck with plain flex track laid straight onto the plywood. Some versions of this system of power delivery have the tube in which the bolts slide soldered directly to the side of the rail. I decided I wanted to make up separate units and have these sitting next to the track with the power being delivered by small lengths of solid NS wire. I hunted through my store of brass tube and rod and found I had what I needed for the job. I’m not sure of the dimensions of the materials I used. I would guess that the outside dia of the tube would be 1/4″ and the rod I used for the two bolts is an appropriate dia to slide in this. My suggestion would be visit your K&S supplier and do some tests. You’ll find a size that suits your needs.

I began by running wires to the alignment dowels and connecting these up to the DCC bus wires. These were connected on both sides of the gap between modules and deliver power to a terminal block. I also ran wires to the short section of track that lies between the end of the scenic portion of the layout and the train turntable. I made up two sets of units that would form the basic components. Two bolt units (left and right-handed) and two “receptacles” (the parts where the sliding bolts would be driven home). I used solid brass (25mm wide K&S material of a suitable thickness) to form the bases of these. I didn’t need to isolate these items from anything else (after all they would be sitting on the wooden surface of the baseboard) so I could use solid brass and forego the use of paxolin. I soldered these up using my big 80w iron and then screwed them into position using small self tapping screws. I’d pre-drilled the holes for these screws. I made sure the screws were short enough not to emerge below the wooden surface of table, thus interfering with the turning action.

I only had time to make the four test units but so far I’m happy with the result. The units hold the track in alignments and deliver power to the rails. The bolt units were hard-wired to the terminal blocks with a length of insulated wire and the receptacles were connected to the track with some .8mm NS wire. I only need to make the two bolt units but I need to make sixteen receptacle units in all as I have four lengths of track: four for each length of track. I’m dying to test a loco across the gap and over the bridge but this will have to wait till next weekend.

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One thought on “Fiddle Yard Power

  1. Found your blog today. Very interesting. I particularly like your buildings. I would love to see more about your use of clay for making buildings. I love trains and dollhouses so it combines both my passions. Any advice you could share on making bricks would be appreciated. IndyPoppy

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