ATSF 3460 Blue Goose Build

[nscaler711]

I am guessing this thing is out of the question?
http://www.ebay.com/itm/N-Scale-Con-Cor-J3a-4-6-4-Hudson-Steam-Engine-Santa-Fe-Blue-Goose-/161485664689?&_trksid=p2056016.m2518.l4276

[superturbine]

I am guessing this thing is out of the question?
http://www.ebay.com/itm/N-Scale-Con-Cor-J3a-4-6-4-Hudson-Steam-Engine-Santa-Fe-Blue-Goose-/161485664689?&_trksid=p2056016.m2518.l4276

Ah, yes

[victor miranda]

hoo boy...

lets avoid needless complication.

building driver/axles/bearings and getting them true is a difficult enough task.
the centers of the hiawatha drivers are plastic.  So forgo the electrical pick up
from the bearings.
For now. plan to use the tender pick-ups.

Then the task at hand becomes get the Hiawatha drivers onto the CC geared axles
and bearing in the CC bearing blocks.

lets get it on its feet and see if it needs more pick-ups.

victor

[mmagliaro]

There is quite a difference in conductivity between nickel and silver paints.  Nickel is about 1 ohms/sq/mil and silver is 0.02 ohms/sq/mil.

I don't think that .02 number is right.  The MG datasheet for Silver Print says 0.2 ohm * mil

In any event, I think for the distances and coating thicknesses involved here, the nickel resistance
and voltage drop will be insignificant.  Tell ya what.  I will go do a test coating and take some measurements,
and report back.


EDIT:
And Victor's point is well-taken that the mechanical complications of making this thing physically work
are far more difficult and important than driver conductivity at this point.
But it would be good to know if some sort of coating can work.

[Cajonpassfan]

And Victor's point is well-taken that the mechanical complications of making this thing physically work
are far more difficult and important than driver conductivity at this point.
But it would be good to know if some sort of coating can work.

No question.... the mechanics of this thing are complicated and there's no tolerance for errors of misalignments. As I said earlier, I'm not yet sure I can make it all work properly, at this point it's just an excercise in feasibility. But the electrical pickup is important to me and brushing on some conductive paint to connect the rims with the washer/collar assembly doesn't seem all that hard, see pic, but of course time will tell once I have the needed materials.
Max, I'll be definitely interested in your conductivity test results.
Victor, welcome to the conversation, I'm always interested in your contributions.
Regards, Otto K.

[peteski]

I don't think that .02 number is right.  The MG datasheet for Silver Print says 0.2 ohm * mil

In any event, I think for the distances and coating thicknesses involved here, the nickel resistance
and voltage drop will be insignificant.  Tell ya what.  I will go do a test coating and take some measurements,
and report back.

Max, the specs were taken from the datasheets.
Silver: https://www.chemtronics.com/descriptions/document/Cw2200tds.pdf
Nickel https://www.chemtronics.com/descriptions/document/CW2000TDS.pdf

I try to use (within affordability constraints) the best product for its intended purpose.  Here I'm not too worried about the voltage drop during regular operation (which will be probably less than 0.3A under full load).  I'm worried about the shorts which could melt the wheels.

IMO, nickel paint would work just fine in low current applications where there is no danger of shorts (like LED headlight or motor circuits).  But with nickel paint used on a plastic center of large drivers, there might be enough heating during a short to cause damage.

If the specs I quoted are correct, if the painted metallic line is about 0.03" wide and about 0.15" long (over the plastic center) then the resistance of the nickel paint will be around 5 ohms.  Then co complete the path, the current will travel down another similar trace on the other wheel.  So total resistance of that short will be 10 ohms.  In normal operation this will introduce only a small voltage drop through the motor. But if those wheels are ever place directly across the rails of DCC track power (at 12V) the 10 ohm resistance will pass 0.84 A of current.  Not enough to trip a breaker, but each trace on each wheel will dissipate close to 5 Watts of power. That will most likely quickly heat the tiny trace to the point of melting plastic. 

With silver paint the trace on each wheel will be around 0.25 ohms (0.5 for both wheels).  A short at 12V would pass 25 Amps (more than ample current to quickly activate the circuit breaker).

I have not experimented with the nickel paint - this is all just theoretical musings - assuming that the specs I read are accurate.

[draskouasshat]

I agree with Victor on this one.  enough with the conductive lube/paint/putty  discussion. without a mechanically sound mechanism ready to work, there will be no need to worry about picking up track power at all.

[mmagliaro]

Peteski,
You are correct about your data sheet.  The MG Chemicals data sheet has different numbers for their silver-based product.
(Although I think there is a mistake in their sheet, because the product description says .066 and then the data sheet says
0.2, which seems kind of high for silver).

They also make a http://www.mcmelectronics.com/product/MG-CHEMICALS-843-20G-/20-5895
silver-coated copper.

The jars are about $16, $34, and $56, respectively, for nickel, copper/silver, and silver.
Those circuit pens you are mentioning are about $22, so that does look like a better buy if you
can draw on the back of the wheel and make it work.

As for resistance, I think your calculations are in the ballpark.  And yes, a short through that stuff could still be trouble.

I think the reason it works well for me on a Mikado driver is that MOST of the path is actually still be carried by the little
phosphor bronze finger along the back of the wheel.  The only place where the chemical goo has to carry the current
is across the tiny gaps at the wheel hub and the wheel rim.
When I get it right, I can get those resistances darn near zero (perhaps a few tenths of an ohm from axle to rim).

Perhaps that's the way.  Glue a little phosphor bronze strip in place on the back of the wheel, and then
overcoat it with conductive Goo.

[superchief]

nscaler, yes that is the con cor version of the kato j3a hudson(as noted comes with a seperated flywheel, but not attached!!) the only thing on it that is CLOSE to correct is the paint, Santa Fe's only streamlined engine is #3460(was not persevered), not 3461, when asking Jim Conway of Con Cor fame why they made a second number , he replied "you NTRAK guys like to doublehead" and "I replied, then where is the FRONT coupler?" this is the holy grail of Santa Fe steam engines, and it needs to be done right!!!! Gordon

[nscaler711]

I am sorry guys, i was trying to be funny, I already know most of Con Cor stuff is worthless (tell that to sellers on eBay  ) for prototype modelers.
I did however see a Streamlined Japanese steamer somewhere in N that was a 4-6-2 and its Drivers were huge... ill keep looking, it might have been a Kato, Micro Ace or Tomix, i bet you could use its chassis and wheels... like I said I'll keep looking and post a link when I find it.

[nscaler711]

I think I found it...
http://www.ebay.com/itm/Micro-Ace-Manchuria-China-Eisenbahn-Railway-Streamline-Steam-Loco-4-6-2-N-Scale-/400808975692?pt=Model_RR_Trains&hash=item5d52139d4c

http://www.ebay.com/itm/Microace-A8407-Manchuria-Railway-Steam-Locomotive-Type-981-Light-Gray-N-scale-/201215659177?pt=Model_RR_Trains&hash=item2ed9634ca9

I have no idea if this will work for you or not but it may be good kit bash fodder for another locomotive.

[superturbine]

I think I found it...
http://www.ebay.com/itm/Micro-Ace-Manchuria-China-Eisenbahn-Railway-Streamline-Steam-Loco-4-6-2-N-Scale-/400808975692?pt=Model_RR_Trains&hash=item5d52139d4c

http://www.ebay.com/itm/Microace-A8407-Manchuria-Railway-Steam-Locomotive-Type-981-Light-Gray-N-scale-/201215659177?pt=Model_RR_Trains&hash=item2ed9634ca9

I have no idea if this will work for you or not but it may be good kit bash fodder for another locomotive.

That engine has spoked driver we need Boxpok drivers for this build.  Thanks for trying tho!

Jason

[mmagliaro]

Wait...
That MicroAce engine may have merit.

According to a thread I dug up from the archived Atlas forum, the MicroAce A8407 has 13.3mm drivers.

That is 83.77".  That means that the Hiawatha drivers would fit that frame without having to relocate
the axles. 

MicroAce + replacement drivers.  Not a cheap solution, but I bet that MicroAce engine runs great. 

[peteski]

MicroAce + replacement drivers.  Not a cheap solution, but I bet that MicroAce engine runs great.

I have one of those.   It is really large and chunky (it is a 1:150 model of a large steamer).  It also uses a huge motor (which barely fits in the cab).  I haven't really given it a good test yet but it is nowhere near Kato quality.  If you guys would like more details about it I can dig it out of the stash.

[superturbine]

I have one of those.   It is really large and chunky (it is a 1:150 model of a large steamer).  It also uses a huge motor (which barely fits in the cab).  I haven't really given it a good test yet but it is nowhere near Kato quality.  If you guys would like more details about it I can dig it out of the stash.

Yes Pete,
Please share details.