Monday, 24 July 2017

The Disappearing Fiddle Yard

The last couple of weekends I've been building a "domestic" fiddle yard for Hexworthy. If I exhibit it I'll use the large 5-track traverser/turntable I built for Awngate, but while ideal at exhibitions it is big (and frankly, ugly), and the Household Authority has made clear it is not welcome as a permanent addition to the lounge!

All I need at home is a couple of sidings, as I don't really do serious operation. The layout fills the bookcase so the sidings need to overhang (over the printer and hamster cage!). A slimline, low-profile design was needed.

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This is the result - a discrete tapering shelf, which attaches to the layout using the same split hinges. OK, the shelves need tidying, but the layout is reasonably neat. But if that is still too intrusive, simply lift the end up...

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By use of some paste-table type hinges (left over from a previous incarnation of my son's trainset) the fiddle yard swings up, and over...

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Until it is stowed over the layout. When I've made a lighting pelmet for the front of the layout the stowed fiddle yard will be largely hidden.

I had planned to make this a simple deck for a point and a couple of tracks, however this would have meant very short trains if the board was not to hit the ceiling! (Yes, I did check). The front edge track entry position, and tapering front edge, also made a useful arrangement of tracks tricky. However I realised a sector plate would work well - albeit, is more complex to make, especially as it has to hang upside down!

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The deck of the fiddle yard is a double thickness of PVC foamboard, the top layer forming the sector plate supported on the lower deck. As seen here a lip was fitted to the rotating edge of the plate in a slot in the deck, supporting it when upside down - and hopefully ensuring no vertical movement of the deck tracks relative to the entry track.

Talking of track, the next job is to lay some!

Monday, 10 July 2017

Off the rails

Last weekend Amberley Museum held their annual Rail Gala, I was there on the Saturday with the Sussex Downs 009 group demo / 009 society stand. There were some good narrow gauge layouts in the exhibition hall, while outside both steam locos operated an intensive service with most of the extensive selection of i/c locos running demonstration trains and generally having fun. There's a collection of photos here.

At lunchtime my son and I decided to eat our sandwiches on a bench at Brockham station, to enjoy the fine weather and the trains going by. This is the mid-point of the line where trains cross, and we watched a goods train set off behind a Hudson Hunslet diesel, before stopping suddenly...

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Caught out by the catch point! Oops.

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As you can see, the loco is well clear of the end of the rails. Even travelling slowly it takes a while to stop. So, out comes the jack and some big timbers.

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And slowly the loco is jacked up to be slid sideways onto the running rails.

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"Nothing to see here!"

The passing loop being blocked meant only one train running for a while.

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"Problem? What problem?"

Finally re-railed, and with no damage except a slightly bent but functional point operating rod (and perhaps someone's pride), normal service was resumed. Still, it was an excellent demonstration chaps!

Thursday, 29 June 2017

Emery paper and masking tape

I have been making slow progress over the last few months with two 3D printed Diesels, a Narrow Planet Baguley-Drewry and a CWR Hunslet, both as used at RNAD depots. I was keen to get a good surface finish so spent much time with fine emery paper, then a coat of primer, more rubbing down, this was repeated 4 or 5 times until I was happy the print lines were gone. These were both good quality prints, but the effort in surface preparation is worthwhile.

The recent fine weather was a good chance to spray with the top coat - I chose Halfords enamel dark green, as I've used for other locos, and looks rather smart. The rattle cans give a good finish with little effort, so I decided to spray the black frames and roof too.

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This is the first time I've used masking to spray different colours, and I was very pleased with the result. It helps that the break is between body and footplate so lining up the tape straight is easy, and there's little chance of bleed under the tape. I used Tamiya tape (yellow) for the edges, which sticks well with a clean edge but low tack, and "domestic" masking tape for covering the bulk of the model in between.

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After spraying a few coats of Halfords black enamel, the exciting bit is peeling back the tape!

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The Tamiya tape was carefully pulled away with tweezers. I'm very pleased with that finish!

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You may notice I haven't yet fitted the etch components including the bonnet sides, I thought it might be easier to paint this way. The etch has been blackened, primed, and painted separately.

So now the details are being brush painted with enamels. Buffer beams get a coat of white followed by two of red (I considered yellow and possibly even wasp-stripes, but I do like red with the green). Cab interiors are cream. You may notice another loco has made it to the paint shop too...

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Monday, 12 June 2017

Urban Transport - With a difference!

Back in May half-term we had a holiday in Italy, and made a couple of day trips into the nearby city - Venice. Everyone knows Venice is an unusual city in having canals instead of roads, and you probably picture the stereotypical image of the traditional Gondolas in a serene setting. Of course the truth is a busy and sometimes congested city - which as someone interested in transport generally, I found quite fascinating.

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Here's the Grand Canal - the main thoroughfare of the city - right outside the station (far right behind the bridge). I can't see a Gondola, but there are at least 10 water-taxi's visible, and three Vaporetto's - these are the water busses, the public transport system of this city. The one outside the station to the right is just departing from the bus-stop, the yellow and grey shelter on a pontoon. I'll come back to the yellow craft in the centre later.

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Here's a typical Vaporetto that would operate on the Grand Canal and to nearby islands. The Vaporetto's are the Underground system of Venice, albeit with a better view, providing a frequent service through the city and the "suburbs" around the wider lagoon for residents, and tourists too. This one holds over 200 passengers, the large gate behind the driver's cabin allowing commuters to board and leave the craft quickly at the stops, which have near-level entry platforms (floating) and modern electronic ticket systems. Routes are numbered and colour coded, with a London-Underground style schematised route map, making travel around the city easy.

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Here are a couple of smaller Vaporettos passing in Murano, an adjacent island, which operate the less busy routes and use narrower canals. I think they are more attractive boats though they are still highly functional, with the wide gates and standing areas. Meanwhile much larger boats operate the commuter routes around the lagoon, up to triple-deck vessels carrying 900+ people as we used to get into the city.

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The water taxi's are all to the same, elegant design. The driver (is that the right term?) is up front where passengers can board, there is then a comfortable cabin and behind that an open deck. Here I spotted a boatyard with one out of the water, while the one in the foreground is entering the strops used by the crane to hoist them out.

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At last, a quiet canal with a Gondola! But what's that noise? The bin-lorry doing the rounds, but of course this is a different sort of garbage truck. I find the working boats more interesting than the touristy Gondolas. Note the driver-operated crane for the wheelie-bin, which has bottom doors to ease emptying into the barge. Beyond is a delivery barge, the Venetian equivalent of a Transit van, mostly seen carrying drinks and food (in refrigerated versions) to the cafe's and hotels, though I did see one delivering a new kitchen and another with a sofa on it...

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Here's another delivery barge (with it's own crane) being passed by a police boat - of course in this town the police must use boats too! It has a blue flashing light and siren horns on the bow, with a powerful headlight. I wonder if they have a radar gun?

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Another police boat, this time Carabinieri. I'm confused by the multiple Italian police forces, but this one is either more important or better funded than the Polizia Locale, as the boat looks more sleek...

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The police aren't the only emergency service that use the canals, here's an Ambulance (there was one in the picture at the top of the post too). It's fully equipped with medical staff, sirens, and a radar, and certainly seem able to travel at quite a pace.

Oh, and where do you go if you run out of fuel?

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Monday, 22 May 2017

Latching Fiddle Yard Mechanism - A Prototype

The Sussex Downs 009 group are building a new layout, and discussion at the last meeting came to how we'd build the fiddle yards. The design calls for two turn-tables each with 4 tracks, that are able to quickly change between trains and turn them without handling. This is far from a new idea, the traditional design uses a sliding bolt (as seen on doors and gates) to provide both mechanical alignment and electrical contact to each track. A simple idea that works well enough, but in the smaller scales, the need for precise alignment conflicts with the need for the bolt to slide and engage easily, which can mean they can be stiff or fiddly to use.

I saw an idea posted on a forum some time back that used a pivoted lever with a notch that engaged on metal edges aligned with and underneath the tracks, all that was needed was to depress the lever to release the engagement and move the deck until the next one engaged. The problem was it was bulky and required a lot of space below the deck, which the club layout design didn't allow. I felt the concept was sound though, and after some thought I came up with way that a similar idea could work in much less space, and be constructed with minimal need for accuracy and without special tools or skills.

Ideas are all well and good, but the only way to be sure it works in practice is to try it out. So I raided the garage for leftover bits of wood and PVC foam-board, and with literally no expense spared incurred, built a mock-up over a couple of spare hours at the weekend. The size was dictated by the materials to hand - the deck is about 18" long and 9" wide, long enough to demonstrate it - while construction is somewhat crude. I've added other ideas too like the handle/gate. Now, let me show you the idea...

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An over-view with the deck turned to the front track. On the deck are three pieces of PCB to which tracks would be attached, and through them the top of a brass tube/pin protrudes and is soldered. The handle we’ll come to later. To the left is the release mechanism – push the wooden lever to the left to unlock the deck to turn. The lever was an afterthought "improvement" - initially I just pushed the wing-nut (which could have been a nice wooden knob) to the right, but the lever is nicer to use. I guess that's the point of the mock-up!

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Under the deck you can see a brass “latch” (triangular with a notch at the top) attached to a pivoted lever, the free end of which is moved by the release knob (bolt) - and now the lever too (fitted after I took this photo). The support for the deck is shaped for a particular reason.

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From underneath you can see the three location pins (brass tubes) protruding down through the deck, and the latch arm locking mechanism which pivots on the lower wooden block, the other end slides on the upper wooden block.

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The latch arm close up, the bottom is the pivot, the top rotates as per the arrows, and is pushed by the bottom of the wooden lever. The high-tech tension device (rubber band in this mock-up, but a spring would be better!) pulls on back the latch arm. The bass latch can be seen with a wire from it, and against one of the slopes a location pin can be seen from the deck. As the deck is rotated this slides up the brass latch by pushing against the lever until it drops into the vee shaped notch, holding it securely and making electrical contact between the brass latch and the PCB above.

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The location pins only protrude about 5 mm below the deck so clear the frame of the board – the foamboard is 5 mm thick - and at the top, protrude just far enough to be soldered to the PCB, and not foul locos passing over them. The rest of the mechanism is contained within the frame. This makes it reasonably straightforward to build this mechanism, and contain it within a conventional design and depth of baseboard.

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Back to the handle. In the up position the tracks are clear, but when pushed right over the bottom of the handle uprights contact the supporting board below stopping excess movement. With the handle folded down the deck is free to rotate beyond the last track – i.e. can turn right around - as seen here.

Operation is simple: simply push the lever  to disengage the pin and rotate the deck, once the lever is released the deck latches at the next track that it aligns with. As the brass pins are round, and the notch is vee shaped (with rounded entry), alignment is actually very precise - as the pin reliably self-centres in the vee. No effort is required by the user to achieve this, the deck is simply rotated until the pin clicks into place. Electrical contact is also made connecting the aligned PCB (i.e. table track) to the fixed track.

This system would be just as useful on a traverser or sector plate as a turn-table, and had I thought of it a couple of years back, I'd have used it on my "exhibition" fiddle yard for Awngate instead of the micro-switches. Some of the construction details could be improved from my quick mock-up, but overall I'm happy to say the concept works well.

Wednesday, 10 May 2017

Decoding the Wiring Enigma

I don't do a wiring diagram, but I do plan out the wiring before I start. The key is the track plan, with track feeds marked, and a "code" given to each feed, point, and indeed each wire. The wires are connected from switches to track and point motors, via terminal blocks, following the codes to label each wire.

Hexworthy has just four points, I've labelled A to D. Each has a feed to it's frog (in this case, the wire dropper from the PECO points) which is switched by the point motor, and I've labelled them Af, Bf, etc. There are 5 switched track sections labelled 1-5, I put the feed into the rear rail (as the wire is less visible) and only gap that rail, so fewer "common return" feeds (labelled R) are required. Because of the live frog points breaks are required in both rails of both joins between the red and green sections.

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The switch wiring schedule is pretty straightforward, the table above shows the wire codes for the input and output of each switch. "T" is the controller track output, and "P" is the point motor power from the capacitor discharge unit (CDU). Note that the sections may be fed from the adjacent track, so for example section 5 is only live if section 4 is switched on and point C is set to the siding, as well as switch 5 being on.

Wiring to and from the switches is via screw terminal blocks that make the wiring easier to follow, make joining wires easier, and providing a point to de-bug if needed. There are terminal blocks for the incoming power supplies (from a 6-pin DIN socket), the connections to the panel, and as shown previously - one for each point motor which includes the frog switching as well as the motor connections. From the track plan it can be seen which rails are being switched, so the inputs come from the section, return, or previous frog feed - this saves extra wires to the rails. Example terminal block connections are shown above, the colours indicate the wire colour used.

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This is the result with all the wiring in place - surprisingly complex for such a simple track plan! At the top of the picture the control panel is lifted out to access the switches at the rear, below it the terminal block feeding the switches can be seen. On the right are the connections to the power socket, note that the return wires are linked over two terminals to make room for multiple connections. Below and left can be seen two of the point motor connections. All terminals are labelled with the wire code denoting the connection to switch, point motor, or track, so wiring up is simply joining the dots.

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The other end of the board is a little less busy. All that remains is to tidy the cables, bundling together with tie wraps or a twist of wire, and securing where necessary.

You can see I've cut a slot in the foam-core, that's a hand-hole. I was finding it difficult to find places to grip when moving the layout around!

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Up top the markings for the feed wires can be seen - and if you look closely, the wires can be seen soldered to the rails. I feed the wire through a hole in the board and form the end into a "7" shape, tin the end, and hold it against the rail web while pressing a soldering iron against it until the solder flows - hopefully giving a neat and secure join.

The loco is on a test run. I'm pleased to report it all worked first time! The careful planning has paid off.

Monday, 8 May 2017

Panel Games

Before wiring can commence I needed to finish the control panel, which had been mounted into the front fascia of the baseboard. The schematic is laid out on the computer - I use Word, which has simple drawing tools that allows objects to be drawn to a measured size so the printed size is known. The drawing is duplicated, one has the switches drawn in place - ensuring there is space between them, and marking the centres. This print-out is stuck on the aluminium panel, and the centres of the switches punched.

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I then took the panel into work and used a pillar drill for the switch holes, and not forgetting the screw holes in each corner. These took a bit of cleaning up with various files.

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On the back of the panel I also drilled a small hole part-way through above each hole, this is to locate the tab on the keyed washer that stops the switch from rotating. The second print-out (without the switches drawn on) is cut to fit, including switch holes, as is a piece of clear plastic. I used a piece of packaging, but anything clear, stiff, and about 10 thou thick will do. The switches are mounted through the three layers.

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With the panel screwed in place the result is a neat, easy to follow panel for surprisingly little effort. Recessing the panel means the edge of the plastic and paper layers aren't seen or vulnerable. I've added coloured rubber grips to the section switches to match the diagram, while point motor switches are left silver.

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