The "Ultimate" fiddle yard - refinements and finishing

So, here's where I think the problem is. With the sector plate of the home fiddle yard (left-hand diagram) the latch arm is pivoted in line with the movement of the pin, so it's movement is perpendicular to the pin movement. However, with the traverser (right-hand diagram) the pivot must be set back, causing the arm to be at an angle, and more importantly the movement of the notch is not perpendicular to that of the pin. When the traverser is pulled forward (down in the diagram) the pin pushes the notch away easily, but when pushed back (up) as the arm moves the slope out of the notch is effectively steepened, requiring much more force to move it. 

It had become clear that no amount of adjustment of the shape of the notch was going to allow the traverser to release forwards smoothly while latching positively, and I couldn't move the location of the pivot for the latch arm. Therefore if the traverser was to move smoothly and not jolt so that trains were derailed, a latch-release mechanism would also be required. I gave this some thought since the objective of the latching mechanism was to make fiddle yard operation easy and requiring minimal intervention from the operator, the latch release would therefore need to be easy and instinctive to use one-handed so that the traverser could be moved with the other. That meant it had to disengage the latches at both ends of the traverser, and return to self-latching mode once released. 

This view of the underside shows the solution I came up with. 

• At the top left of this view is a wooden lever on the front fascia of the board, pressing this down rotates a dowel "shaft" which runs across the board (top to bottom on the left of this view). 
• The shaft rotates a wooden arm, the top of which pushes the aluminium latch lever back (left) away from the pins, releasing the latch. 
• The lower end of the arm is linked to another dowel that runs along under the board (left to right in this picture), such that the rotation of the first shaft causes this dowel to push to the right
• At the end of this second dowel another wooden arm is pushed against the aluminium latch at the far end of the traverser, releasing that end too

With the traverser deck removed the two dowels can be seen, with the wooden arms that bear on the latch levers. Pressing the lever on the front left of the board thus pushes both latches back and releasing the traverser to move smoothly. Releasing the lever allows the latches to spring back into place, and so the traverser will then slide into the next latch position.

This view also shows a wooden arm fixed to the deck on the left, this is a "gate" that swings out to prevent runaways from the traverser when it is pulled forward. Held with a single screw it simply pushes back parallel to the board as shown for transport. There is a similar gate at the right-hand end.   

Another refinement is this old bathroom door draw-bolt. The lower part is fixed to the supporting cross member and the upper part is on the front of traverser, engaging the bolt locks the traverser in place for transport. 

As seen in the photos above the fiddle yard board got a coat of the standard grey paint used on my recent layouts, to match with Hexworthy. The smaller home fiddle yard also got a coat of paint. I use grey wood primer from Wilkinsons (although a primer it has a nice finish), I guess I'll need to find another source when this runs out. Mind you, it's oil based, smelly, takes ages to dry, and is a paint to clean out of brushes, so next time perhaps I'd choose a water-based paint!

The paint really smartens the fiddle yard, although I have not painted the deck or moving parts. Here the latch release lever can be seen, as can the two gates that protect the ends of the traverser when pulled forwards. 

So the exhibition fiddle yard is now complete. It seems to work well in the brief tests so far, but will spend most of its life in the garage, I guess the real test will be when it gets used in anger. 

Of course, life might have been much easier if I'd gone for a simpler turntable or traverser, rather than combining the two. The original intention was to have the benefits of a turntable (fast turnaround with no stock handling) while able to turn it when used against a wall at home, hence the need to pull it clear of the wall. Now I can't erect this fiddle yard against the wall at home anyway and as rebuilt it can only turn when pushed back, but decided I might as well continue to use the sliding/rotating arrangement as:

1. I'd already got the sliding/rotating assembly which seemed to work so might as well reuse it
2. The traverser arrangement allows parallel tracks so I can fit more in - a turntable needs space for the tracks to curve at the ends, so less tracks in a given width
3. It actually proved handy. Being able to slide it away from you and rotating it without having to get off a stool and move out the way is quite useful!
4. The double-ended latching arrangement works with a traverser but wouldn't with a turntable. (I expect it could work with a turntable using a common return rail powered through the pivot bolt and a changeover switch for the polarity when turning, perhaps as microswitches set up to automatically switch)

Finally, here's the home fiddle yard in place with Hexworthy. The grey paint looks much neater, again the moving deck is unpainted. The pillar on the right is the reason for the L-shape fiddle yard and why the larger exhibition fiddle yard can't be used here. 

The "Ultimate" fiddle yard - Latching mechanism

The next job in the fiddle yard rebuild was to create a latching mechanism that aligns the traverser tracks to the entry track, and provides power to the aligned track. This uses the same sprung notch and pin arrangement as proven on Loctern Quay and the home fiddle yard for Hexworthy. 

First holes were drilled in the PCB near the end of the traverser deck centrally between each set of rails. Normally I'd fix the track after putting the pins in and line them up to the entry track, but here the tracks are already in place. I cut a jig from brass sheet to slide tight between the rails with a hole dead centre, then used the Dremel in it's stand to drill a vertical hole, first as a pilot then opened up to the size of the brass tube. The holes go through the PCB strip, the 5mm PVC foam deck, then the second layer of PVC foam that forms the protruding lip, this makes sure the brass pins are held very securely. 

The alignment pins are made from brass tube chopped into lengths of about 20mm to go through both layers of PVC foam and protrude about 5mm below. This tube was 3/32" or ~2.4mm diameter, not that the diameter matters that much. 

The pins are a tight fit through the hole so were tapped into place with a hammer, the top just protruding above the PCB, and are then soldered to the PCB. The PCB was gapped to one side of the pin so that it is electrically connected to one rail. The pins are all connected electrically to the right-hand rail looking at the end of the traverser, so those at opposite ends of the traverser are connected to different rails. The protruding lip has been covered in graphite to ensure smooth travel below the fixed end deck.

The components of the latch mechanism:

• A spring taken from a soap dispenser as shown
• A length of aluminium - in this case T-profile - with a pivot hole at one end, and a curve cut and filed at the other, with a V-notch at its centre. There are also 3 holes through the vertical web
• A long screw which passes through a hole in the aluminium, through the spring, and into the block of wood which is fixed to the board.

In this way the screw acts as a limit stop, spring retainer, and tensioner, the three locating holes allow the spring/screw to be located at varying tension and leverage locations. Note that this fiddle yard has TWO sets of alignment mechanism, one for each end of the traverser.

From the underside the aluminium arm is bolted in place with the wire to one rail (labelled "front") connected to it via a washer, it is free to pivot in the horizontal plane. The wood block is fixed to the board too, with the spring between it and the arm pushing the arm away. The long screw both locates the spring and acts as an end-stop for the arm, in this view the arm is at its furthest travel with the end between two of the five brass locating pins. 

When the traverser slides the pins push the arm back until they drop into the V-notch, being a round pin in a vee they locate the track, and being metal they conduct the power to the rail.

This just shows one end, an identical mirror-image latch is provided at the other end of the fiddle yard with the arm connected to the red wire. 

From above with the traverser pushed back the arm can be seen pushed fully out by the spring. The shape of the face of the arm and the notch are adjusted so the pin slides easily into place. Note how the lower lip of the traverser slides under the fixed deck helping to ensure accurate vertical alignment.

The entry track was trimmed and fixed in place lined up with the layout tracks, and also with the traverser tracks when they are aligned with the pin/notch (including both ends of the rotating traverser). A couple of the traverser tracks needed realignment with a soldering iron, but despite the less than ideal order of construction this seems to work well. The fiddle yard connects to the main board with an audio (RCA) lead, the other end of which connects into the choc-block connector under the board.

The extra depth of the rebuilt fiddle yard allowed the pivot bolt to be inserted with the nuts below (Awngate had a very shallow baseboard), this meant only the shallow mushroom head of the bolt protruded. This meant I could make the centre track a through road rather than having two dead-ends, both making it more useful and making the electricals easier, so a short length of track was cut to fit the gap between the existing PCB strips. However, the bolt head caused a hump in the track, and cutting away the sleepers meant the rails touched the bolt head. I carved away the lower part of the rail with the dremel so they sit neatly over the bolt head, and the red insulating tape should prevent any shorts. There seems to be adequate clearance for wheel flanges. 

An overview of the assembled fiddle yard. It can be seen how the two "handles"  lock the rotating upper deck to the traversing lower deck, they are unlocked when the handles are folded down to act as end-stops preventing stock runaways when rotating. Rotation is free and smooth, the latching seems to work well, and sliding the traverser forwards is smooth. However... when pushing the traverser back the latch is difficult to overcome and movement can start with a jolt, which is likely to derail trains.

I realised that the previous latching fiddle yards I have built were sector plates, the curvature of which allows the latching arm to be pivoted at a point in line with the track join, and so the arc of the movement of the arm is perpendicular to the movement of the pin - that is, the v-notch moves directly away from the pin and resistance is equal in either direction (see here). In this case the arms have had to be pivoted some way back from the track join, and despite making the arms as long as possible they must be at about 20 degrees to the line of travel of the traverser. Pulling the traverser forward the pin has an easy job to slide out of the v-notch, but when pushing the angle of movement of the arm effectively steepens the "slope" the pin has to push against to free itself. 

Hmm...

Rebuilding the "ultimate" fiddle yard

Last year I adapted the fiddle yard for Hexworthy to suit its new location, but that has limited capacity and is only intended for home use. You may remember the sliding and rotating fiddle yard built for Awngate, the plan was to use that for Hexworthy too. Of course, it wasn't that simple... Hexworthy has a deeper baseboard, originally overcome by adding battens under the fiddle yard, but that wasn't an elegant solution. Also, when revising the home fiddle yard I'd changed from using split hinges to dowels and catches for board joins. Also, the wiper contacts with microswitches hadn't proved a robust and reliable way to power and align the tracks, and since then I'd come up with a better solution. So, a significant rebuild was needed...

The existing fiddle yard was dismantled, parts of the frame were reused but the plywood ends, front, and rear were cut from offcuts in the garage to suit the deeper board. This took a bit of thinking as rather than building a baseboard and then fitting it with a fiddle yard, I was building the existing fiddle yard elements into a new frame - so had to take great care to get the surface height correct. 

The rotating deck (top) is unchanged but the lower sliding part was trimmed. The larger of the trimmed material was attached under the ends of the top rotating deck forming a protruding lip to pass under the edge of the fixed part of the deck.  Lower cross-beams were added underneath for the runners. The rotating deck is then bolted to the lower sliding deck as before. 

The fixed decks at the end were attached ensuring the height matched the scenic baseboards, and overhanging the protruding lip from the rotating board. The rotating and sliding assembly was then attached via ball-bearing drawer runners to two cross-members, packing under the ends of the cross-members being used to level and match the height. Surprisingly, I managed to get the height matched and a free moving traverser. Previously double-stacked runners had been used to allow the deck to move either forward or backward far enough to rotate, but here I've simply used a single set of runners so the deck must be pushed back to rotate, the fixed deck being cut away to facilitate that within the limit of the runner span. The shelves were recovered from the first incarnation.

Another tricky job was fitting the dowels in exactly right place to get the baseboard aligned and connected to the main baseboard. Again, using a wood template, I got there in the end. The fixed end decks are recovered from the old fiddle yard but still needed trimming as the end plywood was thinner! Nothing seemed simple here. 

Despite the back-to-front build I managed to get the fiddle yard constructed to fit to the Hexworthy baseboard, with a deck that slides to align tracks then slides right out to allow the deck to rotate. The rotating deck with end-gates that also lock the rotating deck to the sliding deck is pretty much unchanged, but most of the rest of what is seen here has been modified or reconstructed. Yes I do seem to over-complicate things! Next up will be the latching and electrical system.

009 Society 50th Anniversary Exhibition - Statfold Barn

Last weekend the 009 Society celebrated its 50th anniversary with an exhibition held at the Statfold Barn Railway. Actually, "exhibition" feels a rather inadequate description.  It was my first visit to Statfold, which is a privately owned narrow gauge railway and collection.

The railway is nice, but the collection of narrow gauge locos in the roundhouse is astonishing...

Not just a collection - I understand that most if not all of these locos are in full working order with boiler certificate. 

There are more locos out of use. There was even one with my name on it!

The roundhouse was the perfect venue for the anniversary dinner on the Saturday night, a real celebration. There was a great atmosphere all weekend.

Well, back to the exhibiton, which had about 50 invited layouts from most of the area groups plus a few extra layouts brought by their owners on one or both days, and trade support including Peco/Kato and Bachmann. The Saturday was only for 009 Society members, and felt like a giant member's day, although with over 900 visiting members (on top of those exhibiting) it was busier than most member's days I've been to. It was great to see old friends and meet new people, including some forum members I'd never met in person. The Sunday was open to the public, and felt slightly quieter but still busy most of the day. 

I took Loctern Quay, and my son was due to take Slugworth & Co., but unfortunately was ill and unable to come. So, I ended up with two layouts. As you'll see below the Sussex Downs group was quite stretched, so I was thankful of help from Will Booth and Harry Mantheakis on the Sunday allowing me to have a better look around (and even a ride on the train). Both layouts performed well, although I was thankful for the continuous circuit of Slugwoth and confess that most of the weekend I just left a train circulating, periodically changing the train. 

Also from the Sussex Downs group were two other layouts - one was Llandecwyn by Martin Collins. 

The other was Kurseong by John Crane, a model of the real station on the Darjeeling Himalayan railway, which was deservedly voted "most appealing layout" by the society members visiting on the Saturday. 

I have uploaded a collection of photos of many of the layouts here, although not a complete record of all the layouts at the show, partly due to limited time and I focused mainly on layouts I've not seen before or rarely see, and partly because some of my photos didn't come out wheel (possibly because I rushed). You will see that the overall standard of the layouts was very good. 

The Society had comissioned a special anniversay limited edition van from Peco. Of course I had to get one, and by the time the show opened on the Saturday morning it was out of the box and running on Slugworth, where it looked at home. In fact it ran around Slugworth pretty much all day so I estimate it must have covered around 2 real miles or so already. 

The 50th celebrations were great fun, well organised, and memorable. Roll on 60 years...?

No crossed wires

As noted, the wall-wart 16V AC transformers have a very similar plug to the 12V DC power supplies used for the LED lighting. Clearly plugging in the wrong power supply could be bad (for the lights), so clear labelling is needed. 

I already colour code my controller (5-pin DIN) plugs red, and the power-box leads (6-pin DIN) blue. As previously explained, Slugworth can now run either from the power-box with the controller plugged into that, and the blue 6-pin DIN plugged into the layout, or with the controller plugged into the layout and a 16V AC supply connected. Here the 6-pin socket is coded blue (no AC) or red (with AC), with the controller plug (red) in place, and the 16V plug and socket coded yellow and labelled AC. 

The LED lighting plug and socket on the other hand is coded green and labelled DC. No confusion there. 

The AC supply into the "mini power-pack" for Loctern Quay is also coded yellow, the transformers being interchangable between layouts. 

And the Loctern Quay lighting supply is coded green. Simples!

Blanche

For my birthday recently my wife got me a very nice present...

Blanche is a "mainline" class Hunslet 040ST from Penrhyn quarry, and this superb model is by Bachmann. It has a high level of fine detail, and a crisp finish including delicate lining. The prototype's outside frames and unusual inclined cylinders with con-rods inside the coupling rods give this model real character and elegance. 

The cab interior is detailed too, and if you look closely you can see a glow in the firebox, this provides a flickering light in the cab as the loco moves. There are also etched plates in the box to be be fitted. As with recent Bachmann models the running is every bit as good as the looks too, smooth and controllable down to a crawl, and being a little heavier than recent Bachmann offerings it should be quite capable. 

While I have pictured the loco on Loctern Quay, it's a little large (long overhangs) for Loctern and of course has the wrong couplings, I've found it difficult to fit Microtrains couplings to Bachmann locos. It will earn it's keep on Hexworthy in due course where it's fine lining will suit preservation era passenger trains. No doubt it will get some subtle weathering nonetheless, along with a crew of course. 

Rethinking power supplies - Slugworth simplification

A while back I discovered that a simple Hornby "wall-wart" transformer could be used to power my layouts, a much neater and more compact solution than an open-frame transformer mounted in a home-made power box (see below). So I thought it worth getting another. This one is a Hornby C912 rather than the C990, it's rated 16V AC at 14VA which I make to be 875mA, so pretty much the same as the C990 which is rated 800 mA at 16V AC. Either type can be bought on ebay for less than £10. 

When I made the "micro" power pack I'd just hard-wired the power lead in, but it seemed neater to fit a plug and socket, and allow the transformer to be interchangable - not least as I like to have a spare at exhibitions. The transformer comes with a 2.5mm (inner) x 5.5mm (outer diameter) power connector, so I used a matching socket from Squires, and refitted a matching plug to the existing transformer. 

Now the folllowing gets a bit involved! There is a risk with these connectors in that the LED layout lighting uses the same/similar type for 12V DC. In fact, the 12V transformers seem to use 2.1x5.5 plugs which strangely fit 2.5x5.5 sockets, very confusing. I think if I adopt 2.1x5.5 sockets for the lighting they will still work with the 12V DC lighting supplies, but while the AC supply 2.5x5.5 plug will fit the socket the inner contact will not be made. This all seems a bit odd! In any case, some clear labelling may be needed. 

The convenience of the wall-wart transfromers has made me rethink my power box strategy. The original design provided not just 16V AC to both controller and layout, and so 12V DC from the controller, but also a high-frequency track cleaner, and a capacitor discharge unit (CDU) for points, all fed to the layout via a 6-pin DIN plug. The idea was that it kept all the complex and relatively expensive components together in a box that can power any of my layouts, rather than having to add them to each layout. 

Now, I no longer use a high-frequency track cleaner, modern motors don't like them and anyway the use of graphite on the rails has made them redundant. I've also found that the points on a small layout can be driven via a simple CDU made of 3 components in a choc-block connector, as provided in the mini power box seen above. However, some layouts - such as Slugworth - use manual points control and don't even need the CDU, so the mini power box is now simply a junction box. Clearly, it can be eliminated altogether...

So Slugworth has been modified by the addition of a 16V AC input socket for the transformer. This is wired into the 6-pin DIN socket. Now a 5-pin DIN controller plug will fit a 6-pin DIN socket, and fortuitously when I first wired my power box leads I matched the controller 12V DC and 16V AC pins between the 5 and 6 pin connectors (although for the controller the 16V flows in, from the power box it flows out). So here the controller can plug into the 6-pin socket and both it and the auxilliary 16V AC supply (e.g. for lighting) are powered from the plug-in wall-wart transformer, with no external junction or power pack needed. 

Of course, as the existing wiring is unchanged the power box can still be used with the controller plugged into that, and no separate transformer is plugged into the layout. This seems a bit complex but hopefully the diagram makes sense.

I did add a thermal trip to the 16V AC supply, I expect these sealed transformers have one built in but better safe than sorry. This trips at 1.6A which may be a bit high, but if there is a short it should trip. 

This view underside of Slugworth shows the existing socket (left) with the controller plugged in, and on the right the new power socket for the 16V AC transformer wired to both the controller socket and to the lighting power circuitry. Of course this is how many people already wire up their layouts, but the approach I've used maintains "backward compatibility" for the existing power box to be used instead, or as a back-up. 

This simple modification could be made to any of my smaller layouts to eliminate the need for a separate power box (and another lead), and just use a cheap wall-wart transformer. Layouts that need a CDU for point control could have the simple circuit added on-board too, although for now the micro power box used on Loctern Quay does that job.