Marchford Creek

Discussion in 'Entries' started by Bullhead, 7 February 2018.

  1. Bullhead

    Bullhead Western Thunderer

    Firstly, a rather belated Happy New Year to all on WT. Santa was very good to me this year, bringing two very useful bits of model making equipment.

    upload_2019-1-20_13-7-22.png upload_2019-1-20_13-7-43.png
    The trestles are fantastic for working on the layout, giving height adjustment and access to the underside. They will form the basis of display for Marchford Creek when (hopefully) the time comes to exhibit. The drill is an excellent bit of kit and is already earning its keep for tasks where I would have made do with a pin vice before. I’m hoping to add more small machine tools to the collection in future, so I can make and modify more items to a high standard myself.

    Other commitments and a severe loss of mojo meant that progress on Marchford Creek was rather sporadic in the latter part of last year, putting me about some way behind schedule. Over the Christmas holidays a good deal of modelling time was available, and work has caught up extremely well as a result. There is a backlog of progress to report on, so I’ll put some posts up over the next few days to bring the story completely up to date.
     
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  2. Simpas

    Simpas Western Thunderer

    I think it's true that some of the bits of kit we aquire leads us to wonder how we ever managed without them. I think the Proxxon might fall into this bracket.

    I look forward to the forthcoming updates.

    Mick S.
     
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  3. Bullhead

    Bullhead Western Thunderer

    Quite right Mick, this item is already in that category. It's the first Proxxon product for me and I'm mighty pleased with it so far.
     
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  4. Bullhead

    Bullhead Western Thunderer

    I’ve always enjoyed things that light up in some way, possibly as a result of growing up with episodes of the original Star Trek series where every control panel and device was covered in flashing coloured lights. An early design requirement for the Marchford Creek control panel was the presence of led status indicators for traverser functions, turnout positions and un-coupler coil operation. As previously documented, I chose to use SMD devices for this for no better reason than I’d got some in stock having found an Ebay bargain!

    The control panel was cut from a piece of aircraft aluminium, drilled and painted using a satin black aerosol. After allowing the paint sufficient time to harden fully, the controls and led indicator board were mounted and wired up. The track plan was marked out using light grey enamel paint after carefully (not carefully enough!) placing masking tape to define the lines. The diagram is superimposed on the pattern of 1mm holes drilled in the panel, which align with the positions of the surface-mount leds on the indicator board behind the panel. The same artwork was used to produce both the pcb and the front panel drilling guide so everything lined up well first time. I experimented with using short lengths of fibre optic conductor through the panel, but it made no real difference to the visual effect produced so for now the holes remain.

    Panel after drilling and painting
    upload_2019-1-25_13-49-14.png
    Panel after addition of track diagram, switches and indicator board.
    upload_2019-1-25_13-49-26.png

    Round the back. Switches and indicator board with local connections completed – ready to be wired up to the rest of the system.
    upload_2019-1-25_13-49-52.png

    With the led indicators illuminated. These show; for the traverser Red= limit of shunt, Yellow = track occupied, Green = track aligned with exit road. Two microswitches wired in series at each side of the traverser give this indication. Both switches need to operate for the green light to show.
    An adjuster is provided for each microswitch to ensure accurate alignment is achieved.
    upload_2019-1-25_13-51-46.png
    On the main part of the layout, green leds indicate turnout settings and blue lights give a positive indication of un-coupler coils being energised.
    upload_2019-1-25_13-50-35.png
    Under normal lighting conditions, the leds show up well and give a clear indication of what is going on.
     
  5. Bullhead

    Bullhead Western Thunderer

    From the outset, I wanted to ensure that there was some variation in track level on Marchford Creek to avoid a flat, lifeless look and to conform with the supposed lie of the surrounding land. This could prove to be tricky in such a small area and end up looking a bit like a skate park if not done with care. Considerable time was spent with the 2D drawings and 3D mock-ups to determine spot heights above board level at a number of critical points. Gradients between these points were worked out to complete the puzzle. The changes in level are, to my eye, fairly subtle but noticeable without being obtrusive. The “main line” rises at approximately 1 in 100 from left to right. In general, the topography of the site is such that ground level drops from the rear right to front left.

    Track beds were formed using various thicknesses of cork sheet either directly fixed to the board or with laminated card bases built up to give the desired height and ensure smooth gradients where required. All was stuck down with PVA wood glue and well weighted until set. Cutting and fitting all this took ages but was well worth the effort.

    Work in progress.
    upload_2019-1-27_16-13-39.png


    End-on view giving an indication of track height variation
    upload_2019-1-27_16-14-0.png

    Track bases complete. Note the un-coupler electromagnet plates.
    upload_2019-1-27_16-14-27.png

    Joints have been filled with wood filler and smoothed ready for track laying. Note also the addition of wood strips acting as sockets for accurate positioning of the buildings and structures. The scenics will give a finished ground level that will obscure these.
    upload_2019-1-27_16-15-53.png
     

    Attached Files:

  6. Pannier Tank

    Pannier Tank Western Thunderer

    Is the Drill a Proxxon TBM 220 ?
     
  7. Bullhead

    Bullhead Western Thunderer

    Hi David, Yes, it is a TBM 220. As standard it comes with a set of 6 collets but I also bought a standard chuck available as a spare with a size range up to 6mm. Hope this helps, Peter.
     
  8. Pannier Tank

    Pannier Tank Western Thunderer

    Hello Peter,

    Thank you for your reply and confirming the Model Number etc. I think I'll take a trip to my nearest Branch of Axminster Tools real soon!
     
  9. Bullhead

    Bullhead Western Thunderer

    Hi David, Good plan. It looks as though Axminster have relaxed their pricing somewhat. Their Axminster badged new model X0 drill may be worth a look - much cheaper than the previous one and has electronic speed control. The old version had some negative write-ups on build quality though.
    Good luck, Peter
     
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  10. Bullhead

    Bullhead Western Thunderer

    Once the track beds had been formed, the entire surface was given a coat of grimy track colour in order to have a uniform base to work on …..
    upload_2019-1-29_13-25-23.png
    upload_2019-1-29_13-25-39.png

    …before track laying operations began.

    Here we see the creative use of groceries to provide optimum contact between track and base while gluing.

    upload_2019-1-29_13-25-58.png


    The track laying process provided some good lessons along the way. Chief amongst these were

    1. Don’t build the track remotely and transfer it for laying next time. It seemed like a good idea at the time, allowing track building and other tasks to proceed in parallel.

    2. Don’t fit the point motors before the track. Four of the six Tortoise motors were perfectly in position. For some reason, the other two did not line up correctly with their tie bars. I managed to correct this fairly easily by bending the operating wires between the fulcrum and the tie bar to give the required adjustment. This has worked ok as no more than 2mm of shift was needed.

    3. The adhesive worked well. My choice was to use diluted Copydex, adopting a mix of roughly 60:40 adhesive to water. This mix gives plenty of working time for adjustment and holds really well when dry.

    4. The cork surfacing was good to work with. Using various thicknesses to suit the aforementioned gradient profile, it proved easy to cut and stick. It was also very receptive to the use of dressmakers’ pins to ensure that the correct track curvature was securely held while the adhesive dried.

    Next time, I think it will be board, track bed, build track in situ, add point motors after the track is completed.

    We live and learn and there is so very much to learn!
     
  11. Bullhead

    Bullhead Western Thunderer

    Here is the finished result, seen from each end of the system. The copper-clad track nearest the camera in the first image will be inset, hence the reduced number of sleepers used.

    upload_2019-1-31_13-25-56.png upload_2019-1-31_13-26-5.png

    Now for a bit of wiring up!
     
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  12. Bullhead

    Bullhead Western Thunderer

    Hello All,

    Firstly, huge congratulations to those selected to go forward to Railex and also to everyone else involved in the competition. It is great fun seeing the stories of such a diverse range of projects unfold. Being placed in the “continuers” section, I’m very pleased to carry on with Marchford Creek in the hope of maybe getting a spot next year. In truth, time had got away from me, I was behind schedule and in great danger of rushing and spoiling the job.

    Work is moving on at a good pace (for me!) and wiring is the current(!) task in hand. This is one of my favourite occupations, there’s nothing better than waving a soldering iron at a bunch of wires! I’ll put some pictures up later to show progress.
     
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  13. Bullhead

    Bullhead Western Thunderer

    Wiring started by making this rather Heath Robinson arrangement of bus bars. These are fashioned from some power cable conductor and 3A terminal blocks and travel the full length of the system (all 1220mm!) along the rear panel. They distribute DCC together with +12v and 0v.
    upload_2019-2-15_13-23-22.png

    The track dropper wires, made of thin tinned copper wire, pass through the board and are soldered to bits of copper conductor taken from 1.5mm2 twin and earth cable in a section of 3A connector block. The connectors are attached to the board by means of double-sided foam tape intended for car number plate fitting. It is very easy then to attach suitable wires for interconnection. I always tin the ends of these first to ensure a good grip in the connector.
    upload_2019-2-15_13-23-50.png

    Neighbouring wires going in the same direction are bundled together using spiral wrap to lead them neatly to their connection points. Soldered connections can be made directly to the bus bars.
    upload_2019-2-15_13-24-33.png
    Next time, I'll get the bus bars under a bit more tension

    upload_2019-2-15_13-25-10.png

    This gives an idea of how things looked a couple of days ago. All the DCC connections are being made to track droppers first. The DCC feed has been arranged with radial connections to avoid any loops which I believe can cause issues in DCC circuits. Once the DCC is sorted, the point motors will be done, connecting the frog droppers to the relevant switch and the motor connections to the control panel.

    Next, the uncoupler electromagnets will be connected to their control pcb and the pcb connected to the control panel switches. After that, there will just be the lighting to go. In between, there is some painting to be done on the front panel and the lid prior to fitting the lights and interconnections.

    STOP PRESS: Despite checking everything carefully as I went along, there's a pesky short circuit somewhere! I've backtracked and traced it to the traverser but need to work sleeper by sleeper to eliminate it.
     
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  14. Pushpull33

    Pushpull33 Western Thunderer

    I'm loving how the layout is coming along and that some of us have not been 'put off' by the judges decision and are carying on regardless. Exposed live 'bus bar's' I've heard stories that exhibition managers have an issue with this. Can anyone enlighten further as I have also used this approach in the past.
    Colin
     
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  15. JimG

    JimG Western Thunderer

    If exhibition managers are worried about live exposed bus bars under the layout, what are they going to do about the track in plain sight? :) I suspect that the story might have applied to bus bars carrying much higher voltages than the DC and DCC voltages normally used by us.

    The highest voltage I put under a layout baseboard was 50V DC and that was to operate ex PO 3000 relays. I never considered it unsafe since my first work environment was in sound control rooms which used PO 50V equipment and I can never remember any safety problems working around it. I think there would be a definite objection to a layout with mains under its baseboards.

    Jim.
     
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  16. NHY 581

    NHY 581 Western Thunderer

    20180719_221151.jpg I use hi-fi speaker wire for my bus bar.

    Here's a view of my latest project which has the wires on the rear of the layout.


    Rob.
     
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  17. Bullhead

    Bullhead Western Thunderer

    Hi Colin, nothing makes a serial procrastinator like me happier than a new deadline to miss! I'll keep going till someone tells me to stop. Can't help with bus bars and exhibition managers I'm afraid - I've never yet managed to build anything worthy of exhibition!
    Jim's reply seems to make perfect sense.
    All the best,
    Peter
     
  18. Bullhead

    Bullhead Western Thunderer

    The annoying short circuit has been easily resolved by running a triangular file through all the pcb sleeper gaps on the traverser and carefully brushing away the debris to remove any stray slivers of copper. A quick test with the meter shows that all the rail sections are connected to the correct DCC bus bar.

    Further progress has been made in the electrical department by wiring up the uncoupler control pcb. This can now be fitted in position and the electromagnet coils added. Note the numbering on the wires to help me get them in the right place!
    upload_2019-2-17_21-45-31.png

    This panel deals with incoming power. First there is a master on/off switch to kill all the electrics on the board. Next to this is a centre-off DPDT switch to provide power to the layout lighting. One switch position activates daylight and the other is for a night setting.
    upload_2019-2-17_21-43-49.png
    upload_2019-2-17_21-44-52.png
    upload_2019-2-17_21-44-6.png

    The main power circuit has a 3A thermal circuit breaker in it and the lighting is limited to 2.2A. Again, I have added surface mount led indicators to show the status of the system, mounted on a piece of strip board together with the circuit breakers. These indicate: Red, power present at switch. Green, power to main circuit after circuit breaker. Yellow, power to daylight circuit after lighting circuit breaker. Blue, power to night light circuit after circuit breaker.
     
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  19. NHY 581

    NHY 581 Western Thunderer

    Crikey!

    I would not know where to start with that lot.


    Rob
     
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  20. Simpas

    Simpas Western Thunderer

    I have every admiration for people who know all about electrics and things like ohms, volts, watts n resistors and all that. I feel sure it can't be all that complicated and it would be great to be a bit more knowledgeable.

    Mick S.
     
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