Author Topic: Linear Motor Tracks  (Read 529 times)

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martink

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Linear Motor Tracks
« on: January 10, 2022, 04:18:09 AM »
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I would like to recruit a small group of experienced modellers who would be interested in trying out my linear motor track system. I only build a new layout every year or two, but it would be great to see what more people could achieve. Using a linear motor track system offers some unique possibilities for complete layouts in the tiny scales, and for animations and scenic features in the normal ones.

The basic skill requirements are decent levels of ability in general modelling and soldering. If you can build and wire a conventional layout, and build a simple electronic kit, then that should be enough.

You may have seen some of the posts or videos of my linear motor powered T Gauge models. Up until now, intellectual property issues and my agreement with the patent owner have meant that I could only make and use this track for my own projects (with a very limited exception a couple of years ago). As of the start of 2022, the situation has changed and these restrictions have disappeared, although there are still some regulatory issues that would obstruct selling commercially.

The general plan would be to have interested modellers spend a month or so sketching out ideas, exchanging suggestions, playing with track plans, etc., and only at the end of that phase decide whether or not to commit and go forward. I would then have a suitable batch of track manufactured for the combined set of projects, while also sourcing the components for the controller kits. Payment would not be required until after this point when all the bits and pieces were ready to ship. Ongoing help and support would be provided via this forum, and hopefully each of you would be willing to document your progress in a suitable forum topic (warts and all).

This linear motor system was originally designed for T Gauge, but can handle trains from 1:720 (two thirds of T) up to Zn30, and even industrial narrow gauge in N. For roads, the range is 1:480 up to cars only in N. Canal boats, trams, etc. are also viable.

The main advantages of a linear motor compared to conventional propulsion are: very reliable running, no track or wheel cleaning, excellent low speeds, long trains, steep gradients, and easy automation. The main drawbacks are: no wheels (models slide along the track), flat (paper) track surface, slightly jerky or wobbly motion, and over-wide double-track spacing.

Each piece of track is a small printed circuit board, which get soldered together into a complete layout, hence the requirement for decent soldering skills. Despite of their unusual nature, these track pieces form a complete sectional track system with the usual pros and cons of such a system. To keep things simple, no turnouts will be offered at this time. I would also prefer to limit things to rail only, but if enough people are interested then the 2-lane road pieces could be included as well. The road and rail tracks are compatible, so you can build a road layout using rail track, as long as the wider curves and single lane are acceptable.

The absence of turnouts means that your track plans will have to be either basic end-to-end or basic continuous run (preferably more than just a simple oval!). The controller can power up to 8m of track, and has built-in automation that is more than adequate for sequences like an end-to-end shuttle or twice-around-and-stop-at-the-station, all with smooth acceleration and deceleration. You can build your own trains or I can include some of my low-resolution 3D printed models (unpainted versions of those seen in the videos).

Prices in USD are expected to be $70 for the controller kit, $35/meter for track, $7/vehicle for trains or cars, $20 shipping from Australia, using PayPal, with a planned maximum of 10 participants.

If you are interested, I would suggest starting by watching (or re-watching!) the videos from one or more of my T Gauge layout topics here, followed by a selection of the other videos from the YouTube channel to get a better idea of the full range of possibilities.

To experiment with track plans, you can use any common track planning software (such as AnyRail) starting with several lengths of T gauge flex track to create the various pieces of sectional track, then copy and paste as needed. The rail straights are 96mm, 48mm and 36mm long; curves are 122mm radius at 45 and 22.5 degrees and 140mm radius at 45 degrees. Double track spacing is 18mm. If the ends don't quite join up, you can fudge it as long as the ends are perfectly parallel and within 5mm or so. For roads, start with HO or S flex track, and straights are 108mm and 36mm, with curves of 54mm radius at 90 and 45 degrees and 244mm radius at 11.25 degrees. There is also a T piece which is equivalent to a 108mm straight overlaid with two 54mm 90 degree curves. Road designs must line up and join properly - fudging is not possible. You can mix and match road and rail, and the 2-lane road track uses the same 18mm spacing as rail double track.

This technology has quite a few subtle differences from conventional model rail, so please feel free to ask questions. Then let's see what happens.

Maletrain

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Re: Linear Motor Tracks
« Reply #1 on: January 10, 2022, 08:19:41 AM »
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One question: You posted that there are no turning wheels, vehicles must slide along smooth track or roadway surfaces.  I can understand that for things as small as T scale.  But for something like N scale automobiles, wouldn't it be better to have free-rolling wheels?  Or do you need friction to prevent Yoyoing type motions?

martink

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Re: Linear Motor Tracks
« Reply #2 on: January 10, 2022, 09:39:45 AM »
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One question: You posted that there are no turning wheels, vehicles must slide along smooth track or roadway surfaces.  I can understand that for things as small as T scale.  But for something like N scale automobiles, wouldn't it be better to have free-rolling wheels?  Or do you need friction to prevent Yoyoing type motions?

It can be done, but it depends on what models you are trying to propel.  All the N scale commercial model cars I am aware of have either static dummy wheels or crude rolling wheels.  The linear motor track provides plenty of drive force forwards and backwards, but the side forces generated for steering are much weaker.  The simple rolling models I have looked at will tend to either keep moving in a straight line or have an alignment issue that causes the vehicle to veer off and/or miss curves.  Even with sliding static models, you have to be careful that none of the fixed wheels have a tendency to grab the track if the car rocks slightly and so cause it to veer off. 

A few years ago I corresponded with someone who did build exactly what you are talking about: N scale cars with rolling wheels for use with the small oval TeenyTrains tracks.  He built a chassis something like an unpowered Faller car, with the leading magnet attached to moveable steering gear for the front wheels.  It worked quite nicely, but was more mechanically complex than simply gluing a few magnets under a static model.  He did send me a lo-res video, and I have included a screen shot from that but alas I cannot upload the video.  Apologies for the bluriness, but you can just see a magnet on a pole a few mm ahead of the pivoting front axle.

The N scale cars I use are cheap plastic things available from multiple vendors on EBay, but reasonable little models.  I found the best way to get them running was to 3D print a slider frame to hold the magnets, which then gets glued underneath.  I have to carefully file flats on the wheels (deflate the tires!) to make sure they don't grab.




cfritschle

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Re: Linear Motor Tracks
« Reply #3 on: January 10, 2022, 12:48:20 PM »
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It can be done, but it depends on what models you are trying to propel.  All the N scale commercial model cars I am aware of have either static dummy wheels or crude rolling wheels. 

[snip]

The N scale cars I use are cheap plastic things available from multiple vendors on EBay, but reasonable little models.  I found the best way to get them running was to 3D print a slider frame to hold the magnets, which then gets glued underneath.  I have to carefully file flats on the wheels (deflate the tires!) to make sure they don't grab.

I like really the idea of being able to have moving vehicles on layouts or modules, especially at public shows.  However, this seems like going to a lot of work when the moving vehicles do not represent the "best" that N scale has to offer.  All of the Athearn, Atlas (and RPS), and Trainworx vehicles have free rolling wheels.  Also, the Busch, Herpa and Wiking models made with recent tooling also have free rolling wheels.

I think seeing the wheels rolling as the vehicles move along the roadways would certainly be more appealing.   :)
Carter

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martink

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Re: Linear Motor Tracks
« Reply #4 on: January 10, 2022, 02:07:15 PM »
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I like really the idea of being able to have moving vehicles on layouts or modules, especially at public shows.  However, this seems like going to a lot of work when the moving vehicles do not represent the "best" that N scale has to offer.  All of the Athearn, Atlas (and RPS), and Trainworx vehicles have free rolling wheels.  Also, the Busch, Herpa and Wiking models made with recent tooling also have free rolling wheels.

I think seeing the wheels rolling as the vehicles move along the roadways would certainly be more appealing.   :)

It would certainly be nice, but it is a matter of time and effort and tradeoffs.  If you compare the wheels and chassis of those models with those of mobile units such as the Faller or Tomytec bus systems, I suspect there would be a noticeable difference.  However, I haven't investigated this other than taking a quick look just now at a couple of 5-year old non-powered Tomytec models I had in the spares box.

My main design goal for road layouts was heavy traffic - being able to quickly build and run a large fleet of vehicles with tens of cars instead of the one or two buses of the battery-driven systems.

It might be possible to do something by simply widening the axle holes to give the wheels more room to move up and down as well as fore and aft.  The model's weight would be completely supported by the magnets and slider, which would be set to give a slightly higher than normal ride height.  The wheels could then just dangle down and touch the road without taking any weight.  There may not be enough friction to turn the wheels reliably.  The lack of active steering (fixed front axle) might be manageable if only the wider radius rail curves are used.  Some experiments would be required, so I might give it a go over the next couple of days.

rray

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Re: Linear Motor Tracks
« Reply #5 on: January 12, 2022, 08:43:56 PM »
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I would be interested in Z Scale vehicles. I can solder, and assemble electronic circuits, including SMT. I don't need the wheels to rotate, but it would be nice if the vehicles could go up and down slight hills. Where are the links to videos of what you have done so far?

-Robert
If you see it, get it, for tomorrow it may be gone!
Oh, and most importantly...NEVER do today what can safely be sloughed off till tomorrow!

martink

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Re: Linear Motor Tracks
« Reply #6 on: January 12, 2022, 11:52:40 PM »
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I would be interested in Z Scale vehicles. I can solder, and assemble electronic circuits, including SMT. I don't need the wheels to rotate, but it would be nice if the vehicles could go up and down slight hills. Where are the links to videos of what you have done so far?

-Robert

My most recent topic here on RailWire showed some experiments in a range of scales, including Z scale cars and trucks.   The other videos are on the same YouTube channel.

https://www.therailwire.net/forum/index.php?topic=52887.0

Those electronic skills are more than adequate - I stick to basic 0.1" through-hole components, and the tracks are comparable.  I made a quick-and-dirty assembly video a couple of years back, showing the track assembly process.  Since then alignment pinholes have been added that make the process considerably simpler, and I will revisit that video when needed.  Apologies for the quality - it was my first attempt at an instructional video, and I can see a **lot** of room for improvement.   :oops:

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The system can comfortably handle gradients of 10% (1 in 10) or better, as long as there is a gentle transition.  However, the system does not like sideways tilt - the side-to-side steering force is much weaker than the fore-and-aft drive force, and even a slight camber can cause trouble, so I avoid gradients on tight curves.  The track PCBs are thin enough that they will curve vertically as required, so allowing one full track piece (100mm or so) to transition between level and 10% is fine.  For that sort of layout, I use a 3mm plywood trackbed since its flexibility is comparable.   




martink

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Re: Linear Motor Tracks
« Reply #7 on: January 13, 2022, 02:59:40 AM »
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A few pictures of the track pieces and assembled controller kit...