Update As Promised: Miniature Chassis Through Turnouts

[up1950s]

Um, it runs on Z-Scale track.

Z-wizz , I did not know that . So can it be refitted with N scale axels and wheels ?

[narrowminded]

Yikes, that's light!  Even at 15g, that's only 3-3/4g per wheel.  And when I was experimenting with my tender and you were doing weight experiments, I seem to recall about 8g per wheel being the "reliability" point.
Of course, with wipers directly to the wheels, that improves things immensely because you don't have to worry about conductivity through a rotating axle in a bearing.

Are you still thinking of making this in a variation with 33" wheels and 5'6" axle spacing for an ordinary steam loco tender truck?  The potential to use this as a tender drive in steam locos is tremendous.

Actually I had suggested 5 grams as a minimum and up to 8 grams for really reliable.  That was based on my previous testing that was using commercial wheels, plated brass with steel axles.  I hadn't made my own wheels or gears yet at that time, focusing primarily on the drive and motors.  This is the first I've run the final drive parts of my own manufacture, the one piece nickel silver wheel/ axle and also my own gears.  I'm thinking that the nickel silver wheels must make more difference than I would have guessed.  I don't know what else to attribute it to.  And while that runs well as those videos suggest, at that weight it can stall when running at really low speeds.  Not often but it can and also not completely predictable when or where as it goes around.  It might go for hours but might stall in one hour.  That's why I usually weight it to 15 grams if I'm leaving it unattended, just getting running hours.  That just runs and runs, no quit.   I was thinking I was going to treat 20 grams as my bare minimum while striving for 25 to 30 based on my extensive early testing but as I get more testing hours in and over a few configurations I may amend that a little.  I just don't know yet but I AM pleased with these new findings.  Unexpected bonus where I wasn't even looking for it.   Oh, and those new wheels and gears are performing EXCELLENT!  Although, I WAS expecting THAT.

Yes, I'll having those wheel sizes and I'm sure more.  At present, from my first run of a hundred or so wheels, in N scale are 24", 26", and 33".  In Nn3 (Z) are 24", 24" wide, and 33".  And somewhere in this bit of testing I will make up some side rods to try on one of these.  That'll be coming sooner or later.  It's been fun to see things coming together.  And honestly, even though I've been messing with it for a while now, I still marvel at some of it.

[narrowminded]

Can this design be made to a true narrow gauge (.225")?  I would love to convert a CC RGS Goose.

Jason

With these same parts it might be able to be done but that is pushing it a little.  But when I have some of these current projects completed and a run done I will be working on a few more things that might lend themselves to that narrow and maybe even some more.  I've already got some plans. 

Is that a gauge you are running?  Hand laid track, I suppose?  I'd love to see any pics you might have.

[narrowminded]

So, I wonder: how does it do on Micro Trains track?

Mark in Oregon

My original test track was a MT loop and I have one semi-functioning used MT switch.  The switch is fine but one of the rails leading out of the switch is loose in the bed.  It's totally away from frogs and potential trouble areas but makes it fussy.  I suspect I can fix it with some CA but just didn't try yet.  The original prototype (II) ran really well through it and I have every reason to think these next ones will, too.  I'll be testing that at some point so will make a little phone video of that and post it up, too.

[narrowminded]

I'd be so interested in this to make a Conrail 0

That should be doable.   Will you be interested in switching with it?  And not in Nn3 (Z) as shown but in N scale, I'm sure.  What size wheels are on that?  They look bigger than anything I've made this far but can be done down the road.

[narrowminded]

Very interesting and very quiet . How fast or slow will it pass over a standard Kato turnout , and an Atlas Code 55 turnout ?

I haven't tried those yet but will be soon.  I'll need to pick up a few.  Anybody got some that work enough for a test loop that they would be willing to part with?   Nearly all of my testing this far has been focused on the Nn3 (Z) chassis but because they are interchangeable parts I did swap the wheels out for N scale ones and ran it on some N track for about an hour.  Some of these units will have that flexibility.  Change from N to Z with just a wheel swap.  No tools, pull out the Z and pop in the N, gauged on the money, ready to go.

I do know that Atlas Code 80 with the plastic frog won't work with the chassis shown when used as a four wheeler, not one of two trucks on an eight wheeler, because the wheelbase at 44" is shorter than the plastic frog.  I will have a longer wheelbase unit and will test it but that is still begging for trouble as you WILL be operating for some distance depending on just one wheel picking up flawlessly.  That's asking a lot.  With two trucks, eight wheels picking up, Code 80 shouldn't be a problem.  Are there any other turnouts that you know of that use a plastic frog like the Atlas code 80's?

[narrowminded]

Thanks to all who have shown an interest.   It's my little obsession but the encouraging comments are appreciated and encourages me to keep at it.   Thanks.

[peteski]

  Are there any other turnouts that you know of that use a plastic frog like the Atlas code 80's?

Peco insulfrog.
Then there were either Model Power or Life-Like ones which looked very similar to the Atlas one. But those are probably out of production. I think Bachmann turnouts have plastic frogs.  Then there are some European brands with plastic frogs (don't recall which ones specifically).

[narrowminded]

Peco insulfrog.
Then there were either Model Power or Life-Like ones which looked very similar to the Atlas one. But those are probably out of production. I think Bachmann turnouts have plastic frogs.  Then there are some European brands with plastic frogs (don't recall which ones specifically).

I have a Bachmann that has a metal frog.  It's probably every bit of twenty years old judging by the way it came to be here.  I've never used it and probably won't but could test with it.  I only have the one piece.

[mmagliaro]

Actually I had suggested 5 grams as a minimum and up to 8 grams for really reliable.  That was based on my previous testing that was using commercial wheels, plated brass with steel axles.  I hadn't made my own wheels or gears yet at that time, focusing primarily on the drive and motors.  This is the first I've run the final drive parts of my own manufacture, the one piece nickel silver wheel/ axle and also my own gears.  I'm thinking that the nickel silver wheels must make more difference than I would have guessed.  I don't know what else to attribute it to.  And while that runs well as those videos suggest, at that weight it can stall when running at really low speeds.  Not often but it can and also not completely predictable when or where as it goes around.  It might go for hours but might stall in one hour.  That's why I usually weight it to 15 grams if I'm leaving it unattended, just getting running hours.  That just runs and runs, no quit.   I was thinking I was going to treat 20 grams as my bare minimum while striving for 25 to 30 based on my extensive early testing but as I get more testing hours in and over a few configurations I may amend that a little.  I just don't know yet but I AM pleased with these new findings.  Unexpected bonus where I wasn't even looking for it.   Oh, and those new wheels and gears are performing EXCELLENT!  Although, I WAS expecting THAT.

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This is very interesting indeed.  My tender wheels are one-piece, turned from a piece of nickel silver rod, so the wheel and half-axles are one piece.  But I don't have wipers.  I am still relying on the axle points rotating in a beryllium copper block, which is not going to be as dead reliable as a springy wiper maintaining positive contact on the wheel at all times.

As "unpleasant" as we find wheel wipers, there is no denying that when they aren't dirty, they carry current from the rail to the motor more reliably than anything else. 

[Lemosteam]

This is very interesting indeed.  My tender wheels are one-piece, turned from a piece of nickel silver rod, so the wheel and half-axles are one piece.  But I don't have wipers.  I am still relying on the axle points rotating in a beryllium copper block, which is not going to be as dead reliable as a springy wiper maintaining positive contact on the wheel at all times.

As "unpleasant" as we find wheel wipers, there is no denying that when they aren't dirty, they carry current from the rail to the motor more reliably than anything else.

Keep in mind Max, that your tender wheels are not driven as is the case here.  A force is rotating the wheels down against the rail at the friction tangent, where your tender axles are relying upon mass and BEING pulled (dragged) by the loco.  I would expect to need additional mass to keep the axles in contact.

@narrowminded I am flabberghasted.  That runs fantastic.  Been meaning to speak with you soon!

[narrowminded]

This is very interesting indeed.  My tender wheels are one-piece, turned from a piece of nickel silver rod, so the wheel and half-axles are one piece.  But I don't have wipers.  I am still relying on the axle points rotating in a beryllium copper block, which is not going to be as dead reliable as a springy wiper maintaining positive contact on the wheel at all times.

As "unpleasant" as we find wheel wipers, there is no denying that when they aren't dirty, they carry current from the rail to the motor more reliably than anything else.

Are your blocks allowing vertical float, even just a little?  That would be a huge difference on irregular track, even encountering the most minor difference.  Most designs utilizing those axle end point bearings float just a little and the weight of the locos they're in make sure that the necessary slight shift to follow the track occurs.  A three legged stool, when one of those legs encounters a piece of lint or anything insulating, cannot conduct.  That's what's behind the problem with any four wheel loco.  For any of a million reasons, when one axle is not contacting you've got that three legged stool.  And then, if the side that's sitting on one of those three legs encounters any abnormality that causes it to lose that single connection, it's done unless there's something that carries it through that split second failure.   Enter, basic balance, flywheels, capacitors, pivots, etc, etc.  And when possible, combinations of those things.   The more successful those features are the higher probability of success.  One of the best assurances is eight or more wheels where only one each side is actually required.  The odds become very good and what does all of the years of evidence tell us?  Exactly that.

One of my biggest problems in this design, striving for miniature in a device that starts with 2.9 strikes against it, is that there is such limited room for features that we know would work.  If they were incorporated in the obvious ways, all of a sudden it has grown to proportions that defeat the original goal.  And this is what I was meaning when, right from the start, I had said, "This could be the poster child for that saying, "The devil is in the details, but so is salvation".  It's been and continues to be, a fun challenge.

[narrowminded]

@narrowminded I am flabberghasted.  That runs fantastic.  Been meaning to speak with you soon!

Thanks, John.   I loved how you and Peteski asked that question within your first two words on the subject.   You've been there.   One other thing worthy of note, I think, is that it can be configured with 24" driving wheels and with a standard gearing that's fitted in a very compact package while still being very low, prototypical.  To my knowledge there isn't anything out there with drive wheels that small.  Maybe something in "Z"  ?

[mmagliaro]

Are your blocks allowing vertical float, even just a little?  That would be a huge difference on irregular track, even encountering the most minor difference. 

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Well... sort of.  The axles ride directly in the truck sideframes, so there are no floating finger assemblies like on a Kato truck.
However, the truck sideframes are joined together over a plastic center beam with screws and none of that is very rigid, so the 4
corners of the truck can flex.  It's not as free-floating as a Kato truck, to be sure, but with the extra weight I've got in there, I think
it is enough to keep all 4 wheels down even over uneven track.  I have not, of course, gone through months of experimental trials
to prove this, the way you have.   

[narrowminded]

Well... sort of.  The axles ride directly in the truck sideframes, so there are no floating finger assemblies like on a Kato truck.
However, the truck sideframes are joined together over a plastic center beam with screws and none of that is very rigid, so the 4
corners of the truck can flex.  It's not as free-floating as a Kato truck, to be sure, but with the extra weight I've got in there, I think
it is enough to keep all 4 wheels down even over uneven track.  I have not, of course, gone through months of experimental trials
to prove this, the way you have.   

With eight+ wheels you're not having pickup issues, are you?  If not, call it done.   If so, could you loosen those screws a touch to intentionally allow float?  If that helps you could probably make a shoulder for the screw to tighten it while still allowing the float.  Those pinpoint axles probably don't need any additional sprung pickups if the natural action with sufficient weight allows the thing to float and rest uniformly on all of the axles.