Power Pick-up Wheelset

[Lego Dino 500]

If it's going to be possible to support multiple trains on a single layout, then there's a slight issue: While the 9V remains the same, the amperage/draw should increase (double) with every additional motor or pickup. To support this, we'd have to increase the the voltage being supplied to the track, and apply some sort of resistor or mechanism to limit the current draw to 9 volts. I'm pretty sure at least, I'm not the best with electricity. Much like the current draw safety mechanism in Power Functions receivers and motors. To limit costs, it could be possible to limit support to a single motor, and give the option and advice on applying resistors to the pickups to limit power draw and damage to components. 

[coaster]

No, the voltage would be constant, provided the transformer can hold it.  The motors aren't going to draw any more amps than they otherwise would.  The limitation will be on the transformers, in which case you would simply need to add more of them to hold at 9V.

[rjb]

Hello.  We (http://www.cltc.ca - Calgary LEGO Train Club (Canada)) have tried a number of methods to make this work with a DCC layout.  Our lesson's learned would recommend that you need to have spring loaded contact from the side of the track using Silver Nickel metal.  Other metals corrode / tarnish and reduce the ability to pickup power.  On one custom train, I use eight metal wheels (spring loaded bushings pickup the power off the back of the wheel - see Alain le Sage) and they work okay... but only because there are four points of contact on each side of the track at any given point in time.  Granted DCC is more finicky than straight 9VDC.  

I think that if you can come up with a wheel set design, you will do well.  Maybe Kickstarter?  One can use it for anything from power to PF motors to lighting a caboose up at the end of a train to interior coach lighting.  

Wish you the best.  Rudy

[Lazarus]

I have mashed together my own ones from this design and others and a bit of my history with model trains. My goal was to run the power pickups direct to a PF motor to remove the need of 9v motors.

I Ran my prototype at our annual show whats about 24hrs of running and it went ok i would say about 90% successful. I was running it in the Red passenger train, i found two faults what are not a big deal.

1. train could do with some more weight over the power bogey to try and more friction to the power wheels.

2. I need to reduce the friction created by the stock lego wheel holder this is due to the width of the power wheels are more than the plastic lego wheel.

Nothing huge to fix just a bit of sanding and some fish weights. but the concept does work for what i have planned.

[coaster]

On 11/24/2016 at 9:59 PM, rjb said:

Hello.  We (http://www.cltc.ca - Calgary LEGO Train Club (Canada)) have tried a number of methods to make this work with a DCC layout.  Our lesson's learned would recommend that you need to have spring loaded contact from the side of the track using Silver Nickel metal.  Other metals corrode / tarnish and reduce the ability to pickup power.  On one custom train, I use eight metal wheels (spring loaded bushings pickup the power off the back of the wheel - see Alain le Sage) and they work okay... but only because there are four points of contact on each side of the track at any given point in time.  Granted DCC is more finicky than straight 9VDC.  

I think that if you can come up with a wheel set design, you will do well.  Maybe Kickstarter?  One can use it for anything from power to PF motors to lighting a caboose up at the end of a train to interior coach lighting.  

Wish you the best.  Rudy

Thanks.  I plan to simply nickel plate the contacts.  That's what LEGO has done, and it's certainly cheap and easy to do, and should have no problem holding up to this mild usage.

1 hour ago, Lazarus said:

I have mashed together my own ones from this design and others and a bit of my history with model trains. My goal was to run the power pickups direct to a PF motor to remove the need of 9v motors.

I Ran my prototype at our annual show whats about 24hrs of running and it went ok i would say about 90% successful. I was running it in the Red passenger train, i found two faults what are not a big deal.

1. train could do with some more weight over the power bogey to try and more friction to the power wheels.

2. I need to reduce the friction created by the stock lego wheel holder this is due to the width of the power wheels are more than the plastic lego wheel.

Nothing huge to fix just a bit of sanding and some fish weights. but the concept does work for what i have planned.

I'd love to see pics!

Here's an updated overall shot of the wheelset:

A lot of you are concerned about maintaining good electrical contact.  The LEGO 9V motor used spring loaded contacts on the metal wheel flange such that the flange always made contact with the rails, and I'm doing the same thing here.  Popping the cover, here's what the insides look like:

Isolating just the contact tabs, they look like this:

As I said before, this has taken a backseat to the tracks project, but I haven't forgotten about it.  There's just only so much I can do at once.

Edited November 29, 2016 by coaster

[fred67]

I'm extremely interested in this idea; I've done an inventory today and I've got six functioning 9V (disambiguation: I refer to the old 9V system as 9V, the current system as PF) motors, more straight track than I thought I had (and more curves than I know what to do with); with the advent of the new ME Models track looming on the horizon, the issue becomes how long those motors will last.  Despite having more 9V motors than I thought I had, I still have more trains than motors.  I also am not willing to give up the convenience of power from the track, but do like the idea of operating things on the train independently (like lights and perhaps doors).

Some of the suggestions from the past regarding picking up current from the rail had the train actually operating from the rechargeable battery, with the battery constantly being charged by the rail.  I'm not as good with electronics as I'd like to be - and out of the three semesters of physics I took, electromagnetism was the hardest, but it seems to me this would allow the train to operate smoothly no matter what connectivity bumps you have along the way (as long as you're mostly making your circuit).  I still don't want to shell out $50 for the battery - and I want to be able to run any one of my trains at a whim, not have to rebuild the battery into each one (and just forget about buying 5 or six of those things).

So I'm wondering how this would work.  It's the PF adapter to use regular 9V batteries.  I'm wondering if there would be a way to make it work as your capacitor to smooth out the electrical bumps.

EDIT: since coaster posted while I was writing this; the talk above also discussed using more than one of these.  Electrically, do you just put them all in line with each other?

EDIT 2: to make it clear, you'd use rechargeable 9V batteries, of course.

Edited November 29, 2016 by fred67

[coaster]

I don't think so, but I'm not sure.  I freely admit that I'm electrically stupid; I can do some basic wiring, but as far as capacitors go, it's over my head.  My plans for myself though are to use these staggered through the entirety of the train, such that as long as I'm in contact with any tracks that are powered, my motor will have life. 

Not to get sidetracked here, but I don't have a lot of faith in the new ME 9V rails.  I know the design they're pursuing, and the pick-up is intended to be from the top, not the side.  As such, there's a good likelihood you'll intermittently lose contact since you'll only be touching on the corner of the rails.

[legoman666]

I've done some experimenting with capacitors and super capacitors. Regular caps weren't even worth the effort, they only get you about 1/4s of run time if you lose connectivity. Of course, picking a larger cap would lengthen the run time. I've tried 2 different super cap configurations, one was 100F, the other 10F. 10F is plenty, but caps are tricky to use, they are seen by your power supply as a dead short (they have very little internal resistance). So you need a way to limit the current to them. Also, their voltage decreases as you use up their stored power, so you need a voltage regulator. So now you need not only to fit some caps in your loco, but also a current limiter and voltage regulator in addition to your motor controller. I have 4 locomotives built this way using custom power pickups, they work well. The one with the 100F system can go for about 2 minutes with no track power, the 10F systems can go for about 30-40 seconds.

[ScotNick]

9 hours ago, coaster said:

Not to get sidetracked here, but I don't have a lot of faith in the new ME 9V rails.  I know the design they're pursuing, and the pick-up is intended to be from the top, not the side.  As such, there's a good likelihood you'll intermittently lose contact since you'll only be touching on the corner of the rails.

As far as I know the inserted metal rail for the ME 9V rails is just slightly wider than the plastic track itself - as a result it would allow contact on the side as well, but at this point only ME knows...

[coaster]

55 minutes ago, ScotNick said:

As far as I know the inserted metal rail for the ME 9V rails is just slightly wider than the plastic track itself - as a result it would allow contact on the side as well, but at this point only ME knows...

That would be a change from what I saw earlier this year.  It was the exact opposite when I saw it, such that there was about a .5mm gap between the edge of the metal rail and the plastic base.  If they've made that change, then yes, it would work just fine.

[M_slug357]

11 hours ago, legoman666 said:

I've done some experimenting with capacitors and super capacitors... *snip* ...the 10F systems can go for about 30-40 seconds.

I don't think you need THAT much capacitance to bridge the split-second connectivity gaps that coaster's wheelset would undoubtedly experience.

I did a brief experiment a while ago that ran into contact issues between motor & track. I think that these could have been solved if there was a capacitor or two in place, ensuring that the PF receiver was fed a constant voltage & current:

It works (theoretically) by Nick Jackson, on Flickr

In the photo, I have a gutted 9V motor supplying power to a modified PF receiver that is controlling a PF train motor with BBB medium drivers attached.

 

Edited November 30, 2016 by M_slug357
typos

[Lazarus]

@ Coster

What you have there is what i did just not as clean, i would pay for what u have there instantly.

I use copper model train bushes that push onto the back of the 0 scale wheel, both items are designed to do this so i dont worry about contact. 

I was thinking of running a Capacitor but after running i had not need, if running a Receiver or DCC i would recommend a Cap but if just running AC no issues.

[legoman666]

12 hours ago, M_slug357 said:

I don't think you need THAT much capacitance to bridge the split-second connectivity gaps that coaster's wheelset would undoubtedly experience.

It lets me go over unpowered track sections, like ME Models curves. I just keep my straights powered.

[mattmarsden]

Are there any updates on this? I would certainly buy some.

[coaster]

Not at the moment.  I've been preoccupied trying to get the tracks up and running.  I hope to get back to this and have some prototypes by the end of the year.

[mattmarsden]

Ok well please keep us posted as I would certainly be interested in some.

[Trekkie99]

Hey @coaster, I love this idea and am looking forward to seeing further progress. BTW, would a custom electrified third rail which would stud down onto the center of PF train track work? Could you have a wheel set that looks similar yours that would be designed to pick up the electricity from the custom third rail piece where you would then plug the PF train motor into the wheel set? Also, would this be dangerous and could you get electrocuted by touching it? Thanks. 

[ColletArrow]

2 hours ago, LegoMonorailFan said:

BTW, would a custom electrified third rail which would stud down onto the center of PF train track work? Could you have a wheel set that looks similar yours that would be designed to pick up the electricity from the custom third rail piece where you would then plug the PF train motor into the wheel set? Also, would this be dangerous and could you get electrocuted by touching it?

I think you're just describing the old 12v system, as seen here on the left-hand track:

Power was provided to the metal rails from a transformer, and their motors had stud pickups on their undersides, as seen in this image: 

(Neither of those images are mine, I found them on google.)

Regarding your last point, the silly answer is if you want to run your trains off un-transformed 230v mains power, yes!  
The proper answer: no, as you will never be using above 12v for such a system. The aforementioned LEGO one never harmed anyone, unless you placed a spoon or something across the metal rails in which case you will short out the transformer, the same as any metal-railed track system.

Steering back towards topic: @coaster whilst I don't have any use for such wheels as I have no 9v track myself, I can see the brilliance of being able to use track power but individual IR train control, and I look forward to seeing what others can do with them once released! Stick to your plans though; anything you produce will be a boost for the community, and (hopefully) well worth the effort.

[coaster]

3 hours ago, LegoMonorailFan said:

Hey @coaster, I love this idea and am looking forward to seeing further progress. BTW, would a custom electrified third rail which would stud down onto the center of PF train track work? Could you have a wheel set that looks similar yours that would be designed to pick up the electricity from the custom third rail piece where you would then plug the PF train motor into the wheel set? Also, would this be dangerous and could you get electrocuted by touching it? Thanks. 

That would be a completely different animal.  You could utilize the old 12V system rail as ColletArrow suggested.  Using that as your 3rd rail with power and then the 9V tracks as the common would get you a 3-rail system, but other than building reverse loops, I don't see what we'd gain from that.  Could it be done, sure, but I don't think there'd be a lot of interest in that.  It wouldn't be dangerous, no, unless you're planning to run this off a car battery.  

[Ludo]

Hey @coaster,
Just bumped on this tread and I like this wheelset but have some questions/remarks.

I notice the cable connection on the wheelset, but how to deal if you want to use 2 of them next to eachother and using the original bogie plate, making a double axle bogie 4x6 (example : Emerald Night coach)?

You can connect only one of them, because the connector for the second wheel pick up can't be placed because the first one sit in its way.

What would you think to extend the power pick up contacts to the long side of the plastic casing, making it possible to 'daisy chain' the wheels? Then you need only one cable to connect, but you have 4 wheels making contact (2 on each side) with the track and a more reliable power pick up. 
Wouldn't the cable introduce more friction on the R40 & points and derail the train/coaches? The 2 wire cable from the 9V era posed some problems in the past, but with the 4 wire PF cable it's even worse (very stiff cable). Personally, I prefer the cable wires to pas trough the pivot pin of the bogie plate, this eliminates the problem of the extra friction, and the wire is not visible. I know it's not an easy task to create a wheel pick up that suits everyone's needs.   Specially for the ones who build there brickbuild bogies as close to the real thing.

Best regards.

[coaster]

Hi @Ludo, if you were to double these up 4x6 as you say, I would connect the back 2 studs to the 9V cable, and then connect the 2 wheelsets together with a 2x4 electric plate.  The coupling would then sit on top of the electric plate, and the bogie plate finally on top.  The 9V wire would then run through the center of the carriage, similar to powering headlights on an old 9V set.  Does this make sense?  I can mock it up in LDD later if it would help.

 

[Ludo]

Hi @coaster,

Your explanation make sense, I understand what you mean,and doing it this way, it looks ok.

The only problem i'll see - now and in the future - are a lack of affordable priced 9V cables and 2x4 electric plates. 

What do you think from following idea.

9V cables are already expensive, and certain of them have a pulverizing isolation ( specially the rectangular formed cables with a kind of rubber isolation - I own a few of them and worthless to use due to short cirquit!). These days, cables used for Arduino are very cheap and available around the world. So if you could use a 2 pin (or 4 pin to secure the electrical contact) female socket on the wheelset (Dupont connector or similar with or without locking), and you can plug in a male Arduino cable in it (or a pin header with pins at 0.1"" spacing - they are most common used), would make the 'system' cheaper on the long term, and those connectors are widely used and available in the electronics world. If for practical reason (production cost) an inversion of the male/female connectors is nesesarry, ok for me, as long as the pins on the wheelset are hidden in the wheelset to prevent bending of the pins (damaging) if wheelsets are stored in a bin, shipping, ...

I'm convinced that the 9V CABLES will disappear on a middle to long term (who buys them nowadays? Only for replacement of an old cable? And @ what price?).And while you create a compatible wheelset with power pickup, I would leave the 100% LEGO compatibility, specially concerning connectors and wiring and go for a widely used and cheaper solution. Or you need an extra mold to make 2x4 / 2x6 / 2x8 plates with electric contacts like the one you mentioned in your reply and how many will you sell on the long term?

thats my idea. 

[M_slug357]

I agree with @Ludo on this; time to abandon the older style electrical connectors!

I think an interesting way to connect multiple wheelsets together might be to use the 1x4 spaces that are available on the underside for electrical connectors? Arduino pins or something similar.  Assuming many might make a standard 4x6 bogie (two wheelsets together), having two units be able to directly couple to each other would be beneficial. I would mainly use a product like this for internal lighting for coaches, for example.

[Capparezza]

20 hours ago, Ludo said:

9V cables are already expensive, and certain of them have a pulverizing isolation ( specially the rectangular formed cables with a kind of rubber isolation - I own a few of them and worthless to use due to short cirquit!).

Yeah, had this problem on one of those connection cables from Transformator to the Rails. However, replacing those cables is very easy, nothing in those connectors is soldered. Neither the 9V-connector nor those rail conductors. Just get a cheap and thin 2-wire cable (slim speaker cables or whatever), pry apart the connector, rip out the old cable, put the new one in and firmly press the connector together. The wire isolation gets cut by pressing the connector together and is thus making the electric contact.

I have done this already and it's very simple to do, can post pictures if you're interested. So, if the connectors are in good shape you can use those over and over, just put new cables in.

 

20 hours ago, Ludo said:

I'm convinced that the 9V CABLES will disappear on a middle to long term (who buys them nowadays? Only for replacement of an old cable? And @ what price?).And while you create a compatible wheelset with power pickup, I would leave the 100% LEGO compatibility, specially concerning connectors and wiring and go for a widely used and cheaper solution.

Are 9V cables still available from LEGO? I thought they are out of production anyways, all you can get are those PF - 9V extension cables. So yeah, even stock on Bricklink or other sites will dry out someday, that's for sure. It's definitely a better idea to get rid of them when designing a new feature.

[Ludo]

Hi @Capparezza,

I've replaced in the past the wires from one cable with 2 colored Flatcable wires, and agree that you can replace the old wires with new ones. But the problem is to split the bottom plate from the top plate without damaging it too much. It can be done, but is a bit tricky.

found this weekend an other cable with pulverizing isolation, just on the exit from the 2x2 plate. Time to repair it also.

found disintegrating isolation Inside a 9V train regulator too, so it's not due to sunlight that the isolation is disintegrating.