# Adding Kadee Couplers to USAT SD 70



## jr747 (Feb 7, 2008)

I just bought a new USAT SD 70.  Kadee recommends using the #831 for using it on 8' diameter curves.  When I got my engine, it already had the USAT knuckle couplers on it but did not come with the hook and loop couplers and I think the 831 needs the arm that the hook and loop coupler attaches to.  Have any of you come across this?  Am I missing something?


 


Thanks.


 


J.R.


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## NTCGRR (Jan 2, 2008)

I installed 789s on mine , but you have to do alittle cutting and a longer screw.
I don't remember any other couplers in the boxes


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## aceinspp (Jan 2, 2008)

This engine will take some modes to put anything but USAT couplers on it.  I installed AC couplers and it took a little extra work to get them right.  Later RJD


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## Jim Agnew (Jan 2, 2008)

I cut the "tang" off the USAT coupler, drilled a hole in the end and mounted a KaDee #1835. I also beveled the top corners of the #1835 to allow for more swing in the pilot opening, which then provides enough swing to negotiate reverse 8 foot diameter curves when double-headed.


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## NTCGRR (Jan 2, 2008)

I'm sorry 
keep forgetting to post a photo of how I did it.


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## jr747 (Feb 7, 2008)

Well, I went to Charles Ro and got the mounting that would normally use the hook-and-loop couplers.  I had to take the origanal pedistal off and mount the new pedistal with the swing arm that the kadee #831 attaches too.  I'm glad I went back to Charles Ro to solve the problem and now I've got Kadee's on my new SD-70.  Last night, I was pulling a train with it.  The Phoenix sound card was going, the smoke was blowing out the top....it was sweet!  I love this engine!  /DesktopModules/NTForums/themes/mls/emoticons/w00t.gif


J.R.


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## Guest (Mar 15, 2008)

JR,
Can you post a picture of the completed coupler and the mount?
Thanks Nick..


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## Greg Elmassian (Jan 3, 2008)

You might just reference the Kadee site which describes the 831 or 836 mounted to the pedestal. You can download the file: 
http://www.kadee.com/conv/USATrainsSD-70%20MAC.pdf 

Regards, Greg


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## Guest (Mar 16, 2008)

Thanks Greg , i saw the web site ,but was wondering HOW Marty got 789's on them and if they were stronger...
Thanks Nick.


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## Greg Elmassian (Jan 3, 2008)

Right Nick, sorry. Marty has commented that the 789's are stronger since they are "center set" as opposed to "offset". From a pure standpoint of physics, it would seem so, since the forces on the coupler would be mostly tension, where the offset coupler would have a torquing effect in addition. 

Now, the question is: have you ever broken a coupler because it was not strong enough, and specifically snapped the knuckle off the shank? I do not believe it is something that you need to consider until you start running trains in 100 car lengths. 

I will add something in though: Under heavy tension, your biggest problem with Kadees is that they slip over each other. On truck mounted couplers, the offset shanks can add torque and the springing of the truck and the long "tang" all help this happen. On body mounts this is less of course, since you will not torque the whole body. 

Using 789's as opposed to the offset head 831's might help this in certain situations. I use the "standard" body mount coupler, the 830, which has a long shank, no offset, and the draft gear springing. I have no problems. I know some people do not like them since the draft gearbox is much larger. I run mostly USAT and AML freight cars, so these couplers just bolt on in 5 minutes and I have no clearance issues with the wheels and the gear box on 10' diameter curves. 

This works for me, but tighter curves might have you trim some of the gearbox. 

Now, I've spoken a bit in general for all rolling stock, so I should apologize for getting off track, so to speak. 

On locomotives, where multiple units may incur much larger loads by locos "fighting" maybe having the different coupler shank helps? In reality if nothing else is happening, the load on the locomotive coupler SHOULD be the same as the coupler on the first box car. 

I think (guessing here) is Marty's experience is very long trains, multiple locos, locos not perfectly speed matched, so doing all he can to strengthen the locomotive coupler system would surely make sense to me, given his environment. 

Regards, Greg


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## Guest (Mar 16, 2008)

Wright Greg,
 i will go with the 836's as i have them already, speed match won't be a problem as i use DCS keeps all locos at same speed like DCC. i also us mostly 830's and rolling stock so far 42 center flows 48 usa tank cars and many other cars as well ,and they are really strong, the only cars i started using 789's on were the 100 ton hopper cars because were there is real narrow pad and the 789's fit just right. i now have 61  aristo hopper and 6 mth hoppers as well but i had to use #1 couplers on them as there was no way that i could figure ou to put g scale couplers on the mth cars. the are very well detailed by the way.i also am in the process of ordering a bunch and i me a bunch of those new AML bathtub CSX gondola cars to go with the other hopper cars, then maybe i can give Ray a run for his money.... he he he. how hard was it to grind off the stock coupler boxs on the aml box cars. as these are the next cars i have to do, 22 of them with 830's/DesktopModules/NTForums/themes/mls/emoticons/ermm.gif
Nick/DesktopModules/NTForums/themes/mls/emoticons/w00t.gif


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## Greg Elmassian (Jan 3, 2008)

Get a dremel, and a cutoff wheel, the new one with the quick change hub... if you have a light touch, you can cut the "boss" off the mounting pad, then use the flat side of the wheel to smooth the area. Takes about 35 seconds. No sweat.

Also, use the AML screws, then you don't have to try to reach inside the car or remove the floor like the USA box cars.

I have a page on it: (sorry for the crummy pix)

http://www.elmassian.com/index.php?option=com_content&task=view&id=173&Itemid=213


Regards, Greg


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