Automated Shunting with Linear Motor T Gauge

martink Oct 17, 2019

  1. martink

    martink TrainBoard Member

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    This video shows a small test track, demonstrating how part of my next linear motor layout will operate. It will be of a UK prototype, a minor 1930s GWR station, modelled in 1:480 scale (about 7% smaller than normal T Gauge).

    The is a simplified and scripted version of the planned operating pattern of part of this layout, with automated shunting of UK-style 4-wheel wagons (each 12mm long!). The trains are just rough test builds for the moment. The full layout will be around 6' in length instead of the test track's 2', so will be able to handle (and shunt) full-length 40- or 50-wagon trains.

     
  2. rray

    rray Staff Member

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    Very nice. Operates so smooth. Is this a type of sectional track you are developing? I seen the 1:1000 size ones at train shows, but they had a jerky motion, where you video shows fluid smooth motion.

    I was interested it them, but all they had was a simple loop, which is pretty boring, and the track looked like FR4 PC Board material.

    So I hope to see more, and am interested if this can be made to allow sectional track so I could build a 2' x 4' layout, with sidings and programmable automated operation.
     
    Last edited: Oct 17, 2019
  3. martink

    martink TrainBoard Member

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    Thanks. I try.

    My system is based on IDL's, and uses the same coil/magnet spacing standards (the functional equivalent of track gauge in conventional model rail). I started working on it a few years ago, when all they had was those small ovals which, as you say, were nice but limited. Since then, IDL has come out with a commercial sectional track system. They have optimised theirs to keep assembly simple and the electrics even simpler, but at the cost of limited operational potential and a fairly high price-per-foot. I have gone the other way, maximising flexibility but requiring more effort, especially with the electrics.

    So, yes, mine is a generic sectional track system, built as plain old double-sided PCBs, albeit in minimum thickness and using 2oz copper. I keep adding new track pieces as needed for more features or to support different track plans, with gradual ongoing improvements fed in as well. So far, this has required custom-designed electrics for each layout, but I am gradually settling down with standardised techniques and boards for much of that too.

    The vehicle movement is inherently jerky, with that particular coil and magnet combination giving 1mm jumps as standard. However, I use an old stepper motor technique called micro-stepping to reduce this to an effective 0.25mm, which allows speeds down to walking pace in 1:480 scale. AFAIK, IDL does not do this. Subtle tricks such as using certain specific carriage lengths also help (24, 36 and 48mm work best, so the scale of 1:480 was chosen so that the commonest UK prototypes just happen to work out to those numbers).

    That sort of 2' x 4' automated exhibition layout is exactly what I am looking to use it for (the first layout was 3' x 1'6", the second 4' x 1'6", and the one based on this video will be 6' x 2', with increasingly ambitious operating patterns). Unfortunately, while I am doing all this with IDL's permission, I don't have the IP rights to the system and so cannot make it available for sale.
     
  4. Kurt Moose

    Kurt Moose TrainBoard Member

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    Your "Outer Melbourne" layout was the most incredible piece I've seen in any scale, so I'm eagerly watching this thread for more info!!

    Amazing stuff in this scale!!(y)
     
  5. martink

    martink TrainBoard Member

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    Many thanks - as with any exhibition layout, the payback for all the effort is peoples' responses and appreciation. Watching the expressions on their faces at shows when they see it for the first time ... priceless!

    For the new one, I am estimating 6 months to completion, with a hard deadline of 8 months for its scheduled first show in June. There are still a couple of experiments to do while finishing the specs for a new batch of track then waiting for it to arrive, so there will likely be a slow trickle of videos and posts. With any luck, the next one should be of the working 1:480 scale canal lock just next to the station.
     
    Kurt Moose likes this.
  6. ddechamp71

    ddechamp71 TrainBoard Member

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    One thing I've not understood : although track is dummy, is the rolling stock actually rolling on wheels ?

    Or is all electromagnetic run ?

    Anyway, that may lead to a full "true" scale with all kind of operations available. Provided scale low speed is possible, especially for switching operations. Maybe a 120-car drag freight performing true switching on prototypically broad curves, all of this on a 2' x 4' layout.. ;)

    Dom
     
  7. martink

    martink TrainBoard Member

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    The trains slide along the track resting directly on their magnets, which provide a smooth gliding surface. The wheels are just slightly raised, painted features on the side. I can get away with this because the models are so tiny - at any practical viewing distance, you simply cannot see the flaws and the illusion is quite good. In a closeup picture such as this one, those crude details are painfully obvious. To be fair to myself, these are just rough test models with a bit of paint splashed on, and the final ones do look somewhat better. The magnets are 3mm in diameter, and the whole loco is about 1.5 inches in length.

    And yes, near-full-scale operations are very, very doable. My new layout is designed to handle and shunt medium-length UK goods trains. Since each car is self-propelled, there is no limit on the maximum train length, they can handle gradients of up to 10% or so, and I can run them reliably down to 1.25 mm/sec (at 1:480 scale mm/sec is basically identical to mph, so that is just a slow walk). I don't have to worry about dirty track or wheels, or stalling, or derailments when backing up a long rake. And that loco costs me about $2 to make. Coupling and uncoupling only requires stopping the train over a section break and then turning that section on or off. Running a 120-car train on a 4' x 2' layout might be difficult though, since even in 1:480 scale the train would still be 12-15' in length!

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  8. HemiAdda2d

    HemiAdda2d Staff Member

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    Those switchmen are so fast and efficient (and small) that I never even saw them! :p :p
    All kidding aside, that was really cool. Crude in outrageous closeups or otherwise, that is really neat.
     

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