Great Chesterford Junction Part Two

Discussion in 'Members Personal Layouts' started by gormo, Dec 5, 2015.

  1. Chris M

    Chris M If 2 wrongs don't make it right ... try 3 Full Member

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    Hey Gormo,

    That's one big cassette. A couple of questions ... When installed is the cassette always connected to the track power? If so does that much aluminium suck a lot of power from your overall supply?

    Interesting that you are using slotted screws to hold the aluminium to the wood. Do you prefer them or are they just there in your supplies? I used slotted screws all the time back in school where we were taught to always line the slot up with the wood grain. I don't use them anymore as I find the driver slips out of the slot more often than with Phillips screws particularly with power drivers. Although Phillips heads can be just as problematic if you don't use the right size driver. The newer star, hex and square slots are good when screwing into hard timber but they come in many different sizes and when I go to use them I end up wasting time searching for the correct driver bit, often unsuccessfully (so much for my tool organisation).

    Anyway, an interesting project. How many do you think you will make?

    Chris
     
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  2. gormo

    gormo Staff Member Administrator

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    G`day Chris,
    Yes it is a big cassette, however I think you could go bigger provided you had sufficient room to handle them properly.
    The cassette is always connected to the power, but isolated by a point setting.
    Eventually a switch will completely isolate the line, but to answer your question, I have not noticed any power drain from the Aluminium whatsoever.
    I am using slotted screws because I have a bunch of them. I am not too fussy about screws as long, as they do the job, I`m OK.
    I agree a slotted screw is more difficult to work with than a Phillips or whatever, but I have the luxury of time and I am reasonably patient.
    The Marine ply I am using would be regarded as a hard timber for such small screws.
    To make the job easier, I put a squirt of WD40 into the screw hole before putting the screw in.
    The WD40 lubricates the hole and the screw and reduces the effort of screwing home the screw by about 2/3rds.
    Any excess WD 40 is wiped away and whatever is in the hole will absorb into the timber and dry out fairly quickly.
    I am also putting the screws in by hand screw driver. I find it`s easy to over compensate with a power drill on screws this small.
    I will make a minimum of 7 four foot cassettes, however if I choose to make smaller ones, which is on the cards, there could be maybe 12 .??
    We`ll see how it pans out.
    :tophat:Gormo
     
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  3. gormo

    gormo Staff Member Administrator

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    G`day Folks,
    Nearly there.
    I just have to do the end stoppers now, although I`m doing a redesign at the moment.
    My original design is not a universal fit due to variation in shaft size on the shelf supports I have been using.
    I know it`s a minor detail but it`s niggling away at me from the depths of my mind.......Anyway...:tophat:
    The handle supports have now been fitted

    IMG20240712153232.jpg

    The connecting plates have also been fitted.....we have 100% electrical connectivity now.

    IMG20240712161139.jpg

    And the timber dowel handles have been fitted also.
    The handles are spaced at 400mm

    IMG20240712163523.jpg

    Further testing has proved successful from both ends of the cassette....so all I need now is those end stops.:scratchchin:

    :tophat:Gormo
     
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  4. ianvolvo46

    ianvolvo46 Staff Member Moderator

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    Up to your usual high standard Gormo :thumbup::thumbup::thumbup:
     
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  5. Jim Freight

    Jim Freight Full Member

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    Excuse me for asking but why would the aluminium be a power drain?

    Jim :)
     
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  6. gormo

    gormo Staff Member Administrator

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    I have no idea Jim.....:faint::scratchchin:
    :tophat:Gormo
     
  7. gormo

    gormo Staff Member Administrator

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    A simple solution to the end stops.

    A piece of 40mm x 20mm standard pine cut to suit the inside dimensions of a cassette plus a bit of wiggle room.
    The piece is drilled right through the center to accommodate a 6mm wall plug.
    The wall plug is set to the correct depth and held internally by inserting a screw into the internal end of the wall plug and screwing it home.
    Very simple.......parts readily available.....and it works effectively to protect the stock from doing the leap of death onto the floor.

    IMG20240713110117.jpg


    IMG20240713110056.jpg

    Job done....:thumbs:
    :tophat:Gormo
     
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  8. gormo

    gormo Staff Member Administrator

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    G`day Folks,
    I`ve completed a 3rd 4 foot ( 1200 mm ) cassette today and it has tested OK.
    The only new touch is that I now round off the corners on the end stops

    DSCN0284resized.JPG

    The storage drawer is becoming a bit more tidy.

    DSCN0285.JPG

    And a very short video showing a test run.



    :tophat:Gormo
     
  9. gormo

    gormo Staff Member Administrator

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  10. Vinylelpea

    Vinylelpea Full Member

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    Another great video, I never knew Aluminium was such a good conductor of electricity. Learn something new everyday. :thumbup:
     
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  11. Jim Freight

    Jim Freight Full Member

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    Hi Vinylelpea.

    Aluminimum has about 60% of the conductivity of copper and weighs about 30% less, industrially it can also be a cost effective alternative to copper depending on the cost of raw materials which varies on global markets.

    So, it has a trade-off in some industrial applications, keeping to our uses it's slightly higher electrical resistance would not be noticeable for low current and low speed train operation, however aluminium is a 'dirty' metal, which in our context means the surface becomes dirty far quicker than the nickel silver we generally use for our railway tracks. As usual the dirt acts as an electrical insulator.

    It would become quite noticeable as it gets dirty as the trains will slow up for a given applied voltage.

    In Gormo's application it works well even though it needs more frequent cleaning than nickel silver.

    Plenty more techie info e.g. :-

    https://www.wellste.com/electrical-conductivity-of-aluminum/

    Jim :)
     
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  12. Andy_Sollis

    Andy_Sollis Staff Member Moderator

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    I tried and failed making some of these for Oakamoor a number of years ago. I couldn’t get them work reliable. Now I wonder if this was down to not scraping a sucufficent contact surface or not..? Maybe after seeing Gormo’s wonderful creation I may have to revisit.
     
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  13. Jim Freight

    Jim Freight Full Member

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    Quite possibly, Gormo's contact arrangement looks quite substantial.

    Jim :)
     
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  14. gormo

    gormo Staff Member Administrator

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    G`day Folks and thanks for your comments and input Phil, Jim and Andy.
    As Jim says, the electrical properties of the Aluminium really are no concern at the low voltages we use on model railways.
    I have never had any problems with my cassettes other than needing the occasional clean as you would do with track.
    Aluminium bought straight from the hardware looks pristine, however oxidation could be present and also any other contaminants from the manufacturing process may be present, although not visible to the human eye.
    During the process of the build, I use WD40 to remove any sticky labels and also use it to lubricate drill bits whilst drilling.
    The WD40 is wiped away with a rag frequently during the process, and this in itself starts to clean the Aluminium before any dedicated cleaning process takes place.
    When a part is completely finished, I rub down the surfaces with steel wool to remove most blemishes created by filing, drilling or marking out.
    When the cassette is fully assembled I rub it over again with the steel wool, especially the rails to ensure I have a clean surface to start with.
    It`s important to thoroughly brush over all the parts to make sure no little steel wool fibers remain.
    The electrical contact for the cassette consists of two sets of two prongs clamped each side of identical pieces of angle.
    The cassette is pushed into the prongs to establish electrical contact under a pressure fit. That`s why I need a lever system to initially extract a cassette from the prongs.

    GCJ00790 (2).jpg

    The ongoing maintenance for cassettes is no more than track.
    If you regularly run your trains you will not need to clean your track as often, by virtue of the fact that the metal wheels are doing the job for you.
    Track that is left for long periods accumulates dust and foreign particles and oxidation not visible to the human eye and consequently makes for poor running due to it`s insulating properties.
    So for Aluminium, as with Nickel Silver rail, good electrical transmission requires cleanliness and sound electrical connections.
    :tophat:Gormo
     
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  15. Keith M

    Keith M Staff Member Moderator

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    Aluminium cables have been used for many years in the electrical industry. Terminations are not straightforward though, as electrolytic corrosion could take place within the terminations themselves, requiring the use of a special compound between aluminium conductor and copper lug and hydraulic swaging tools making installation a longer job. Back in the early 70's in the UK, domestic electrical cabling using aluminium conductors instead of copper (for reasons of cheapness) was tried, but then discontinued as it was not popular amongst installers, and socket/switch manufacturers had to redesign the terminals from screw to clamp fixing to avoid breaking the aluminium conductors on tightening. It was also tried on fire alarm systems to replace the 'Pyrotenax' tubular copper wiring which was the usual choice, and is, I believe, still available, although having been retired from the electrical industry for over 12 years now, I'm not 'up-to-date' with current practice.
    Keith.
     
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  16. Jim Freight

    Jim Freight Full Member

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    Mine and my wifes houses were built in the 1930's and were subsequently rewired around the 1970s, and it seems with aluminium to replace the aging rubber and cotton (judging by some of the dead wiring left behind). This came back to bite us last year as apparently aluminium is not considered safe now for let accomodation (we let the house my wife had before we met), an inspection says it must be replaced in the near future, ouch. The reason given that it loosens in terminals which causes bad connections, which results in resistance, which then generates heat when a current is passed through it and in a worse case scenario, a fire!

    I thought that some of the wire in my house was tin plated copper like equipment wire, but no it must be aluminium too :facepalm:

    Personally I find the same problem can occur with copper as that too undergoes plastic deformation, i.e. it collapses under compression after some years and sockets in particular can require thier screws tightening, much like wires in plugs that get hot.

    A similarly annoying change in the UK was with the consumer unit, originally metal (1970s), then changed to plastic for safety when I had the fuse type unit replaced with one with breakers (2014) and now changed back again to metal, for safety again, these changes cost homeowners and more so those who are responsible landlords a packet, as did wiring installed in a flat as new had to be totally rewired 30 years later because it was now deemed hazardous. It certainly makes work for electricians :hismiley: Keith.

    Jim :)
     
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  17. gormo

    gormo Staff Member Administrator

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    Another one done and dusted and number 5 is being prepared.

    IMG20240723164547.jpg

    :tophat:Gormo
     
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  18. Walkingthedog

    Walkingthedog Full Member

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    Usual nice work.
     
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  19. Jim Freight

    Jim Freight Full Member

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    The dimensions of the drawer unit relative to the useful dimensions of the cassette, in particular the length, certainly makes for very efficient use of available storage, this aspect becomes very important as our rollingstock collections expand like rabbits in spring time :faint:

    Jim :)
     
    Last edited: Jul 24, 2024
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  20. gormo

    gormo Staff Member Administrator

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    G`day Folks,
    Family commitments have slowed me down this week with cassette building and we`ve had a very cold few days as well.
    So I`ve chosen to stay indoors in the warmth for a while.
    To stay productive I am re-visiting a train schedule I came up with a few years ago, because with these new cassettes I am reaching a point where running trains needs a purpose.
    The schedule system, in it`s fairly basic form, worked well enough, however I`ve learnt a few things since I first developed it.
    This is my original idea below.....a rather out there looking schedule but it works.
    The problem with it is that there is no option for sorting wagons, although it could be added in.

    Running Sequence.png

    I have also being doing some research and watching some excellent videos from Saffron Walden Model Railway ( https://www.youtube.com/@SaffronWalden-ro5ks ) which runs on a timetable.
    I won`t be running on a timetable because my set up is fairly complex when you count up all the possible start and end locations.
    So I`ve adopted a schedule that looks a bit like an old fashioned timetable.
    The main advantage is that I`ve almost tripled ( 40 ) the possible moves / sequences contained on one A4 page, compared to 14 on the original idea.
    The concept is that Great Chesterford is the central location and everything else is either UP or DOWN from there.
    I can also add more sequence pages to turn this thing into a rather long session.
    With most scheduling systems I`ve seen, the object is to run all the stock so that finally, it finishes up where it all started.
    I feel if I had a schedule with a large number of sequences, I could stop running say at 25 ? and continue on from there next time, or indeed just reset everything to sequence one if I had to.....so I think there is no need to complete the whole schedule in one session.

    Running Sequence Chart.png

    A small sample of how the moves are entered below.
    The services are abbreviated....Pass being passenger, Mxd being a passenger goods, Gds for Goods and of course a few others to cater for Light Engine, Express Services etc. etc. etc.
    The locations are P1,P2,P3,P4 for platforms.....MD1, MD2, MD3 and MU4, MU5, MU6 relate to the Main LIne fiddle yards Main DOWN and Main UP.
    C1, C2, C3 and more are fiddle yard cassettes from Duxford
    NM1
    through to NM6 relate to Newmarket sliding yard

    Running Sequence Chart 2.png

    To accompany the schedules will be a card system ( still to be worked out ) for Goods and Passenger Goods with instructions about where to drop off and pick up rolling stock.
    To achieve full operation I still need a fuel depot at Little Bardfield and I`ve also decided to put a loading platform in there too, which will significantly add to the operations at that little station.
    So there we are folks.....something to work on through the cold winter nights.
    :tophat:Gormo
     
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