Linear Motor Experiments - T Scale Points and Automated Shunting

This video shows a small test track demonstrating operation of a set of points (or a switch/turnout) for the linear motor track system. This includes a sample of automated shunting in T Gauge, a simplified version of part of what is planned for my next proper layout. The track system is my re-implementation of a product by IDL Motors (www.teenytrain...).

[@AlwaysCensored-xp1be]

I did four layer boards back around 1990. Controller on one, three layers of coils. Induction charging system, never thought about three phase linear motor though. Did see one at University long time ago. Each coil was about 3inchs diameter.

[@modelrailmusings5981]

Mine are just a bit smaller that that, and only use double sided board! A little company in the US (IDL Motors) came up with the idea, but alas, they weren't modellers.

[@AlwaysCensored-xp1be]

@@modelrailmusings5981 How many turns per layer? I used to use 10 turns but at 30mm dia for induction charging. Those phone chargers I think are 125 or 134KHz, magnets might get too hot at those freqs. Regulatory issues are a pain. 3phase stepping on fixed coil spacing would mean variable frequency drivers. Lots of emissions?

[@modelrailmusings5981]

@@AlwaysCensored-xp1be Just 4 turns per coil. I balance the current and voltage by the length of each section, generally 1.0m or so with 0.3A and 12V, so the 3-4W of heat is spread over a lot of track, joiners and wiring, enough that heating is not a problem. It would almost be DC, except that I use microstepping in the audio range to get the effective step size down to 0.25mm, which is how I manage the slow speeds. Emissions aren't an issue unless I were to sell the things commercially.

[@epseagrey8368]

The locomotives look like a gwr pannier and a gwr hall, if I am not mistaken, I also spotted what looked like a toad brake van.

[@modelrailmusings5981]

9 out of 10 - it is hard to tell with those small test models and with my limited cinematic skills, but they are a 57xx Pannier, 40xx Castle, and Toad. You can just make out the Castle's bent steam pipes and set-back cylinders. The 2251 and 31xx Prairie didn't make it to the final cut of this video.

[@andrewmasters5020]

This is great! I'm working on n gauge boxfile shunting layouts. How small would an inglenook in T be? Nah, got to keep focused on my current projects.

[@modelrailmusings5981]

The size of the points and the wide track spacing work out about the same as an ultra-compact N scale track plan, so call it 30cm for a bare-minimum tuning fork layout or 60cm for something more interesting.

[@exveefan]

Man I wish I had your skills. Still have any of my T-gauge wagons?

[@modelrailmusings5981]

I cannot compete with you, Jesse, and others in terms of model detail and such, so I have to carve out my own niche. And yes, I have a pile of your wagons and a couple of steamers that I never got around to painting, bought when I was still planning to do Ribblehead in conventional T. Now, however, all this linear motor stuff is working out well enough that I have switched focus completely. FWIW, your models were the trigger for me getting into T in the first place - otherwise I would still be modelling in N. So, thank you!

[@exveefan]

@@modelrailmusings5981 I'm envious of your success, especially with how reliable Linear motors work compared to T. :-) Would love to make one for Thomas. I sadly haven't touch my Tscale in 2 years due to other demands, and the difficulty in making these work during train shows.

[@modelrailmusings5981]

@@exveefan Those reliability issues with T are the main reason I switched over to this approach. With Sarum, it took a full day of track and wheel cleaning to give 1-2 days of decent running, even after tricks such as wiring 3 power cars together in each train. My Puffing Billy layout has now had 3 days of exhibition running with only two hiccups - once when somebody bumped the layout, and the other when a corner of the paper track lifted. No going back.

[@exveefan]

@@modelrailmusings5981 If you ever decide to make these for sale, let me know. :-)

[@modelrailmusings5981]

@@exveefan Alas, that is IDL's call, not mine. Seriously though, for a basic non-stop roundy-roundy Thomas layout, it might be worth looking at IDL's track, with 3D printed bodies either pushed over their models or with suitable holes for magnets. I can at least advise on that.

[@michaelbujaki2462]

I know how the linear motors work, but how did you do the switch tracks?

[@modelrailmusings5981]

Basically just one track on top of another, and the power switched with relays. Complicated because the lower track is further away from the train so has to have a higher current to compensate.

[@MrRobbowich]

Hi, I have seens your videos and read the articles on your web page and must say that I am very impressed! I am keen on doing some experiments as well - would you be willing to share your PCB-design? Or even better explain the whole electronics and software set up? Thanks

[@modelrailmusings5981]

Hi. IDL has recently granted me a bit more flexibility here, so you might want to contact me through my website.

[@54adrianadrian]

I have a few questions if u ware willing to help? 1. So it works og 3 copper spools wich are powered after each other right? 2. Did u do the rails by ur own or did u order them on a pcb site? 3. Do u have a tip for a controller setup? Maybe 2,5 stepper motor drivers? Also if i dont thing u will do it but maybe share the circuit plan? I think the Patentright from IRL Motors will only count in commercial way so if u share it for free ;) its ok. Thank for your answer your work is awsome and impressing.

[@modelrailmusings5981]

1. Three strings of coils connected at the far end and driven through different patterns of North, South and Off. 2. The PCBs are my own design, and made by a normal board manufacturer. 3. The controller is basically 1.5 normal motor drivers (6 transistors instead of 4), but with special software to generate the right output patterns. I'll see about publishing the controller design sometime soon, and it works with IDL's track. 4. I recently received permission from IDL to allow a few people to use the system on a non-commercial basis, and I am currently helping on a road layout with the first volunteer. I want to see how this turns out before doing any more, but since it still takes a lot of work from my end which I do not get paid for, this will be limited.

[@54adrianadrian]

@@modelrailmusings5981 Ok thanks, looking forward to your work.

[@elliottlambert2921]

Nice, I saw your layout at AMRA Caufield and was really impressed. Did you end up doing an overlay of two seperate PCBs, or is it a single one?

[@modelrailmusings5981]

Thank you - always good to be appreciated! And yes, it is two PCBs. I use 2oz copper, and since the middle layers of a 4-layer board are always the thin stuff, that would be a problem. Also, this way it is built from standard track pieces with just one special straight, so I can easily build other geometries.

[@davidecook2002]

ModelRail Musings where can I buy these units please.

[@modelrailmusings5981]

@@davidecook2002 Unfortunately, I do not have the rights to sell them. The design is based on a commercial product from www.teenytrains.com, which is much easier to use but cannot do as many tricks.

[@plutoyaldnil4750]

I cant believe shunting....I've had more trouble with h.o./00 coaches