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To all,

I want to install traction tires on my 2 USA Trains SD70's. My layout has some pretty steep grades and the non-traction tire wheels can't get the job done. If I install one traction tire equipped axle on each motor block, which position should it be in? The center axle or rear/front axle?
 

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First consideration is as Ted says, are you running track power? If so, not a good idea BUT you do have skates also... so if you want to add more traction tires, put them on the 4 wheels on the main gear block, the outer axles are like pilot trucks and don't contribute much to traction.

If you go this route, make SURE that your skates have good springs (they should move up and down freely, and the springs not collapsed), and TEST the skates to make sure they have pickup.

If you are battery, sure put traction tires everywhere...

I would add some weight, but what is your grade? (how many inches rise in how many feet), and how many cars are you pulling? Have you rolled each car down the grade individually to see if you have any excessive drag?

Greg
 

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Sorry all for the delayed response. Life got in the way.

I was able to secure a new motor block with the traction wheels/tires installed. Unfortunately, this is the only one I can find (USA T doesn't make them anymore). Does anyone have any idea of where I can source the axles/wheels that have the traction tire? If not that, does anyone know where I can source an entire motorblock with the traction tire?

I've looked on the Bay for 2 months now and nothing. :(

Any help is greatly appreciated.
 

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As to the USA Trains SD70 axle that has traction tires,
its part number for a pair of axles is "R22-624 TRACTION WHEELS w/ RUBBER TIRES FOR INNER AXLE" as described in the SD70 owner's manual.
A little picture of them below shows them with traction tires.
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Whilst they are not indicated in the Charles Roe Supply Company website that carries USA Trains SD70 parts, I suggest calling their customer service number, 781-321-0090, and ask if they have the R22-624, and if so, verify they indeed have the traction tires on the wheels. Also, check if you can get the tires by themselves as these can deteriorate and stretch with wear. When they stretch, they come off the wheels very easily.

As to my then new SD70 skates (shoes) -
not making good contact with the railhead, I had noticed a clicking noise associated with it as the loco went down the track.

Having looked closely between the wheels I noticed some of the electrical pick up slide shoes would lift up and drop back down at a rapid rate (vibrate). This was the source of the noise.

On my under house layout, the brass rail head is not as smooth or slippery as stainless steel (used on my outdoor layout) - so this relative roughness have contributed to the lifting effect - captured in the picture shown below. (This noise effect did not occur when the loco was operated on my stainless steel track.)


-Ted
 

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Just curious. How long are your trains that two SD70's can't handle the job?
Typically, I'll run around 10 or 11 of the USA Trains tanker cars (some of the large, some of the medium sized ones and some of the beer can variety). None with excessive drag. My 2 GP9's pull this consist around my layout with no problems; both are equipped with traction tires.

Greg, my steepest grades run around 5% to 6%. And yes, I know this doesn't help. Unfortunately, the terrain in my yard will only allow these grades. :(

Also, I've added about 10 ounces to both of my SD70's. They just aren't getting the traction they need.
 

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Yeah, 5 to 6 percent goes into another world of traction.

So I had G scale legend George Schreyer over my house, I have this 5.5% downgrade, about 50 feet long.

He was sure his weighted SD45 could pull 13 cars up it... it was more like 4-5 40 foot cars.

You did the right thing, USAT diesels are remarkably under-weighted, it's strange. With the "floating" gearbox design, you will want to lubricate the journals with heavy oil often, but they are easy to replace. Note that they will wear away from the ground. You can remove the sideframes, and turn the brass bearing 180 degrees and double their lifespan. I use a very heavy oil there (90w) as opposed to grease, it appears to stay in the bearing better.

Be sure to keep the gearbox lubed with good quality grease, also a drop of oil on the exposed axles is helpful, but the real load is the gears and the axle tips in the side journals.

I think you have it under control as best as possible.... I run track power and hate the look of skates, that has me change out all traction tires for "solid" ones. I believe all wheels the same helps equalize the forces and minimize cracking of axles.

Whenever I service a USAT diesel, I do put the tubing on the gear castings, so there cannot be any cracking issues anyway.

Greg
 

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Thanks Greg. Couple of questions for you:

1) What exactly do you mean by "put tubing on the gear casings"? Do you have some pics? This sounds like a good piece of preventative maintenance advice.

2) Any idea where to look for the traction tire axle? I've scoured the web (ebay, online model train vendors etc...) and can't locate any of them :(

And thanks all!
 

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Thanks Greg. The 2nd link you provided above takes me to a page; unfortunately for me, it says, "R22-624" - wheel & axle set - w/traction tires - main gearbox axles - SD70 (2 axles) (note that later production does not have traction tires). I also confirmed this with USA T.

So I guess the only way I'll be able to secure some is to keep checking the "Bay".
 

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It's the right part number, do they say that they do not stock those parts any more?

The problem is that those wheels were unique to that loco only.

Traction tires should go on the middle or inside axle, does not matter which.

Never on the "floppy" axles.

Greg
 

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I may have a set (or two) of traction tire style axles/wheels for the SD70. But they suffer from the split axles and need repair (I've had good success repairing other ones like this with two part epoxy). Also, they are missing the traction tires. You'd have to find some tires that fit. If you're interested let me know.
 

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Thanks Greg. The 2nd link you provided above takes me to a page; unfortunately for me, it says, "R22-624" - wheel & axle set - w/traction tires - main gearbox axles - SD70 (2 axles) (note that later production does not have traction tires). I also confirmed this with USA T.

So I guess the only way I'll be able to secure some is to keep checking the "Bay".
Here are the two that I have. The one on top has no cracks and is good to go. The one on the bottom has a crack on one side, but I'd be willing to repair it (you can see it in the photo if you look closely). They both would just need new traction tires (which I don't have). If you're interested, I would propose a trade - these ones for your smooth ones. We would be helping each other out as I do not need or want traction tires for my layout. Send me a PM if interested.
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