Penzance 1913

martink Aug 23, 2021

  1. Kurt Moose

    Kurt Moose TrainBoard Member

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    I collect Hawaiian Airlines and Aloha Airlines planes in 1:500 scale, and Herpa has an ICE train and trackage in this scale for they're airport models as well. Pretty small stuff!! I have some of they're GSE "ground support equipment for my airport I'm doing, lot's of good stuff you could probably use for this!(y)
     
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  2. in2tech

    in2tech TrainBoard Member

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    I'd like to see your 1:500 airline collection in an area appropriate as I also do flight simulation as my other hobby, please! Planning on some GA aircraft on my N Scale layout?
     
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  3. martink

    martink TrainBoard Member

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    I've seen some of those Herpa products, and they are nice little models. Not entirely suitable for a pre-WW1 setting though. :sneaky:
     
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  4. Kurt Moose

    Kurt Moose TrainBoard Member

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    I'll round them all up one of these days! Probably have 20-25....:rolleyes:
     
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  5. martink

    martink TrainBoard Member

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    All the buildings have been constructed, both railway and other. The platforms and foundation work for the ground, roads and dummy tracks are coming along too. It is almost starting to look like a model railway.

    Designing the goods shed, loco shed and coal stage was challenging, since all of these buildings are long-gone. I could only find a handful of photos taken from very limited angles, so there is a lot of educated guesswork here.

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  6. Mike VE2TRV

    Mike VE2TRV TrainBoard Member

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    That's awesome!:cool:
     
  7. kimvellore

    kimvellore TrainBoard Member

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    That's some really nice work. The IBL is great for animation but when I got a few of their setup it always moved in jerky motion, every motion was like steps between the coils. I see your video looks real nice, smooth and slow. Is this some custom track coil configuration? or do they have different versions of the tracks?. Their website video also shows jerky motion. Only your videos show ability to go slow and smooth.

    I am sure your videos dont do justice as the scale is really small and only in person one can appreciate the coolness of your layout.

    Kim
     
  8. martink

    martink TrainBoard Member

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    The natural motion of the system is in discrete steps based on the coil spacing. That works out to exactly 1mm for my track and IDL's small oval tracks. They chose a wider coil spacing for their connectable track, so its step size is something around 1.4-1.5mm (a strange number that doesn't work out to anything obvious in either metric or imperial).

    I improve on that by using a software technique known as microstepping, which simulates smaller steps by oscillating or dithering back and forth between two adjacent states of the controller outputs. To move a single step from A to B, I start with A on 100% of the time, then go to 75/25% A/B, then 50/50, then 25/75 and finally 0/100 with A off and B fully on. That gives me four little 0.25mm steps instead of a single big 1.0mm one. Since walking speed in this scale is about 1mm per second, instead of one big jump per second there are four small jumps - a much smoother result.

    Unfortunately I cannot take it any finer than this, because even at 0.125mm the amount of force generated by one microstep is so small that it does not always overcome friction. Some of the carriages move immediately while others decide to wait until the next microstep provides a stronger push. The result is a very strange shuffling effect. There is also a drawback that the oscillation or dithering is done at audio frequencies, so you can clearly hear buzzing and pulsing, much like a traditional low-frequency PWM controller.

    So, it is purely a controller issue, and even then really just a matter of software. IDL could have programmed theirs to do much the same thing, but their idea of suitable speeds seems more appropriate for toy trains - faster is better! To be fair though, the microstepping software is a bit more complex, and their chosen CPU may not have the capacity. It is also a matter of what features we choose to build in to them - theirs has a wireless key fob and can play Jingle Bells, mine has slow running and record/playback automation.

    You are right, the videos don't do the system justice. Comments from people I have talked to at exhibitions that have seen the first two layouts both in person and on video make that very clear.
     
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  9. HemiAdda2d

    HemiAdda2d Staff Member TrainBoard Supporter

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    Super cool!
     
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  10. Mike VE2TRV

    Mike VE2TRV TrainBoard Member

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    What he said!:)

    I work in electronics and the software driving said electronics, and I admire the way that ingenuity and imagination get into the hobby at this scale.
    I really like the software solution to a hardware limitation.

    I've described what kind of hardware is used here to my boss (he has a Ph.D, in electronics) some time ago (as described in this thread) and he's quite impressed and fascinated by the technology. Not bad for someone not into the hobby.

    Keep up the good work!
     
  11. martink

    martink TrainBoard Member

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    The original linear motor PCB track concept by IDL Motors was brilliant. Unfortunately, they aren't modellers. Their products were designed for the tech toy/novelty category, and that really limits how useful they can be for us modellers. Which is why I am doing all of this.

    I usually put in about 2 months of work on the track, electronics and software, adding a couple of new features, then spend a year or so of more-or-less conventional modelling turning that into a complete new layout. A slow process. FWIW, I'm an embedded software engineer, and much of my career has been spent writing software to work around hardware issues, so you are spot-on there.
     
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  12. martink

    martink TrainBoard Member

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    Oops - posted by accident, and cannot delete.
     
  13. kimvellore

    kimvellore TrainBoard Member

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    That's awesome, When I met the owner at a train show and suggested microstepping like a stepper motor to him, he said they tried it all and this was the best they could come up with, so I did not bother with it much. Now that I see how nice it can be after what you have done to it. it opens up a lot more possibilities to using this and making it look real.
    This is a pretty much a linear stepper motor and it would be nice to have these coils overlapping each other with less than 1mm spacing and also having more than one pair of coils powered at the same time, maybe 4 then one can use off the shelf stepper motor drivers and microstep it... When I saw your video on the IBL layout I thought that's what they were selling, that was misleading.
    Also in Micro stepping, you can go the stepper route like instead of 0-100% it would be +- 100% but the magnet polarity must be right. like coil 1 goes 100% North to 100% South and coil 2 100% S to 100% N but that would not work for tracks inclined because there are times the magnetic field will be 0 or too small to hold, again it you can program some hysteresis so the field never goes below some %.
    That's nice you are putting in the time and coming up with all this cool possibilities. Thanks for posting, I enjoy seeing all this and it gets me motivated a little more to get back into the hobby.
    Kim
     
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  14. martink

    martink TrainBoard Member

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    Joking aside, microstepping really is the key to this system, changing it from a toy to a model. I have looked at several possible alternative track and coil designs and spacings, or with multi-layer PCBs, or different interconnect wiring, but IDL's original concept has held up as by far the best and most practicable compromise. Kudos to them. And with microstepping, it all works well enough for my needs, so for the last few years I have focused on minor improvements instead (such as turnouts!).

    The actual coil spacing on each side of the PCB is 4mm, about the minimum practical value since even then the coils only have 4 turns of wire. Overlapping on top and bottom reduces the effective coil spacing to 2mm. Combining this with a 3mm magnet spacing is what gives the 1mm step size - already a four-fold improvement on the basic coil size.

    linear-motor-track.gif
     
  15. kimvellore

    kimvellore TrainBoard Member

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    Martin,
    Thanks for posting the animated gif, it is a great visual in understanding how this works.

    Kim
     
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  16. martink

    martink TrainBoard Member

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    The layout has finally reached the pieces-coming-together stage, with the plastering, puttying and preliminary painting now done. The next steps are the pavements and platforms.

    I still have to decide whether to add more detail to the large area of beach: hopefully just having the tide out should be enough, with a sandbar, wet and dry sand areas, and a little bit of tidal water in Chyandour Brook under the bridge. If necessary, I can always borrow an idea from St. Ruth (a very nice 2mm scale layout set in a slightly later period) and add a couple of erosion-control fences.

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  17. martink

    martink TrainBoard Member

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    Penzance is continuing to progress in fits and starts. The paper roads, footpaths, platforms and tracks are now done. Suitable artwork printed onto self-adhesive label paper is used to make the linear motor track look like something other than a circuit board, and also provides a protective layer for the trains to run (slide) on. The other man-made surfaces have been done the same way for visual consistency.

    Scatter (grass, ballast and sand) will be done later. The next step will be finishing the buildings.

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  18. Mike VE2TRV

    Mike VE2TRV TrainBoard Member

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    That's great work. Thanks for the updates! (y)
     
  19. CNE1899

    CNE1899 TrainBoard Member

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    Martink,
    Nice progress! Your tracks really look good! Are they different from what you have done before?

    Scott
     
  20. martink

    martink TrainBoard Member

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    Thanks!

    Each of these layouts is an experiment, and I do try to improve how I do things with each one. The tracks are generated by a new version of the same program as last time, with a few minor refinements such as different rail and ballast colour (hopefully a better match to the granular stuff I will be using beside the tracks), a paved track option, plus adding frogs and check rails to the turnouts. It didn't work quite as well for the double slip in the loco depot, which looks a bit large and chunky. I may also end up re-aligning the exit tracks on the far side of the the turntable.

    There are similar changes to the road program adding tiles and cobbles, for platform edges and footpaths, since there weren't many painted lines on roads 100 years ago, so otherwise the roads look boring.

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