Update As Promised: Miniature Chassis Through Turnouts

[narrowminded]

An update for those who were curious how the miniature chassis would handle a turnout.  Peteski?  Lemostream?  Original thread is here.  https://www.therailwire.net/forum/index.php?topic=40794.0

And a new poorly shot video of that miniature prototype chassis negotiating some turnouts.  All is working well.   I'm happy.

 

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[jdcolombo]

That's just amazing.

John C.

[peteski]

Very impressive performance.  It goes smoothly through the frogs too. Those turnouts with solid metal frog assure continuous electrical connection.  Good combination.

[Chris333]

Sweet! When do we get to buy these?

[dnhouston]

Really nice work.  I can think of several projects for these.

[mmagliaro]

SO... you've got only 4 wheels and it can make it through turnouts.  Superb, sir!
Are you using wipers on those wheels?  How much does this thing weigh?

I know it has been a long, hard slog refining this thing.  A working 0-4-0 chassis of any kind in N Scale is a Holy Grail.
I applaud you for doing this!

[sd45elect2000]

These may put me a step closer to some really neat electric interurban equipment.

Randy Stahl

[narrowminded]

SO... you've got only 4 wheels and it can make it through turnouts.  Superb, sir!
Are you using wipers on those wheels?  How much does this thing weigh?

Thanks, Max.   Definitely wipers on all four wheels.  They are axle wipers behind the wheels, not wheel wipers, so they are totally hidden.  Another important design consideration is the very low power available from such small motors which affords little extra that can be given up to mechanical loss so it's imperative that any forces other than those needed to drive the thing be kept to a minimum.  The spring force on the wipers is kept low, is directed in a fashion that is the natural direction of the gravity load force on the axles (somewhat but with another subtle design detail in consideration) and from that position, the smallest diameter in the wheel assembly, they have the least possible leverage over the drive.  As axle wipers they also do not induce any side to side load on the thrust face of the worm gear (which sets the end play), another source of unnecessary friction in that latch up.  Then, with each axle and wheel being one piece and nickel silver, the conductivity between the wiper and wheel is pretty reliable.  Then the wheel profiles are quite precise to the NMRA standard and the target gauging on assembly or re-assembly is repeatable within .002" or better.  Press them in with your fingers and they are on the money.  It's the assured, reliable pickup at every wheel at all times that is affording that demonstrated performance and that is a result of the design considerations but then a very precise execution of those design intentions... and clean track.  ... and balanced load... and....    The devil is in the details.

The weight of that particular unit as a bare chassis is measurably less than the chassis for my mine loco which is closer to six feet wheelbase and less than I would build to for general reliability but it works when everything is clean.  It also was not intended to be used as a four wheel power truck but as part of a two truck unit with all wheel pickup even if only four wheel drive.  As my testing results have been coming in I'm thinking I will amend that.   And those turnouts do have their insulated points as well as much bumpier than the video shows.  One is pretty bad.  With that said, the weight as shown in that video and without any tungsten components installed, is only about 7 grams.   And while that isn't much it's still over 30% heavier than the next closest sized unit that I'm aware of which is physically much larger.

When I'm leaving it to run unattended overnight I do add a weight to it which brings it up to about 15 grams, which is what I've arrived at as a general testing weight for my trucks.  (We talked about that with your project.)  That is still a little lighter than I will use as a minimum weight for a finished unit but is appropriate for testing reliability.  At 15 grams it runs without a hitch, all day and all night long.    Maintenance interval seems like it will be around forty hours but that can be more or less depending on the environment.  I'll have something more definitive as I get more testing hours in.

[narrowminded]

Sweet! When do we get to buy these?

Well, thank you, Chris.  The interest is encouraging.   I don't know for sure when units will be ready for sale as there's a lot to do to finish everything really right.  And then to plan, tool, and execute a production run.  But with my own development tools up and running it's much sooner than it was just a few months ago.

I may run a few for sale before to produce in any real quantity just to make sure what the market will be and that all is really ready for prime time.  I'm still working on three more basic variations that I think will be necessary to fill out a line.  I want to test those approaches because I will be trying to standardize the key components as much as possible and I want to make sure they work in each variation.  I'll try to post updates so all can follow the progress and especially add input.  That's very helpful to me.

[wcfn100]

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

Jason

[mmagliaro]

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.

[Wutter]

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

[up1950s]

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

[peteski]

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

Um, it runs on Z-Scale track.

[strummer]

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

Mark in Oregon