# knuckle couplers on Aristo engines



## Joe Herb (May 28, 2008)

Does anyone have any suggestions for eliminating this problem? 

On either my RS-3 or U25-B Aristo engines the trailing car frequently derails on any curves less than 10'. Attaching a heavier car right behind the engine seems to help sometimes but is not foolproof. I am not aware of any hook and loop coupler that fits Aristo engines. Thanks for any suggestions. Joe


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## aceinspp (Jan 2, 2008)

How tight of curve are you trying to operate on. You should be able to make it around at least 8 ft curve before having any problems with derailing. Aristo supply's hook and loop couplers with there locos if you choose to use them. Check you track work for cross level this can also cause problems if your running out doors on floating track. Later RJD


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## engine 72 (Jan 6, 2008)

You can get large Radius cuplers for the RS-3 from Kadee the numbers are 

786 Coupler Conversion, for Aristo-Crafttm RS-3, (4' radius 
track, 2 1/2' with some cars coupled non-delayed) 

787 Coupler Conversion, for Aristo-Crafttm RS-3 
(large radius), U.S.A. Trains® NW-2 (large radius), 
Lionel® GP20 (large radius) 

788 Coupler Conversion, for Aristo-Crafttm Lil'Critter loco 
& RS-3, 4' radius track 

I use the 786 on my RS-3 with no problem on 5' curves. 

Also I think my RS-3 came with a set of hook and loop couplers in the box. 

Good Luck, 

Todd


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## Joe Herb (May 28, 2008)

Thanks for your suggestions which I will look into. The tightest radius I have is 5' but only one section of that radius is used on one troublesome curve. I have not had success attaching the hook and loop couplers that have been in the boxes. Any additional ideas are welcome and thanks again. 

Joe


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## 6323 (Jan 17, 2008)

I've got floating track, 8' diameter curves on the back patio. 
A little uneven in a couple of places that causes derailments of first car. 
A quick adjustment takes care of that. 

Do you have the electrical plug(s) still on locomotives? 
I cut the plugs out of one of my Aristo GP40's. That also helped greatly 
in reducing the derailment problems caused by a coupler that was hampered by the electrical plug wires. Mine, like many others have stated, passed through the 
coupler pocket, instead of the mounting holes just above the coupler.


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## mgilger (Feb 22, 2008)

I'm using my RS-3's on 6 ft diameter curves with no problem. I use mine with a trailing battery control car, so it's a bit heavier than a standard car, plus I use metal wheel sets. Are you running metal wheels or plastic? That might have something to do with it. 

Mark


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## Greg Elmassian (Jan 3, 2008)

Joe, just to be clear, your first post says "derails on any curves less than 10'" I am assuming that is 10' diameter (radius would not make sense). 

Later you state: "The tightest radius I have is 5' but only one section of that radius is used on one troublesome curve" 

So, from your two statements, I do not see you stating that you have curves less than 10' in diameter. 

Further, your second post says the problem curve only has ONE sction of 10' diameter. 

Please let us know what the rest is. 

I run an RS3 all day on 10' diameter curves. I suspect your problem is not one of horizontal curvature, but you have a twist in the track, often called warp, or you have some VERTICAL curves. Check your side to side (cross level) rails to be sure they are level. 

I think you might find other mysterious factors at work here. 

Regards, Greg


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## lathroum (Jan 2, 2008)

I run RS3s and Uboats on 5 foot diameter... and sometimes 4 foot with no problem... 

You need to remove the centering spring... from the coupler on the engine... 

also... the first car must at least have metal wheels... 

just to be on the safe side I put extra weight in the first car... 

You should note, I run indoors... and so my trackwork may be a bit better than outside... 


Philip


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## Joe Herb (May 28, 2008)

Many thanks to all of you who took the trouble to make suggestions on how to deal with my problem. I'm going to check carefully how level the curve is and to run a car with metal wheels behind the engine. Thanks again to all. 

Joe


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## multiplealarm (Jan 3, 2008)

Joe, 
I had the same problem with my U Boat and GP 38"s. I am running 8' diameter curves and no matter what the weight of the car behind the loco it derailed. I put hook and loop couplings on my locomotives and first car. No more derails. Reguardless of what loco and cars I run, the same car(with hook & loop couplers) is always first. I do not like the look of them, but it really solved my problem. Everything else is knuckle couplers. 

Jeff 
Tallapoosa and Southern


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## Paul Norton (Jan 8, 2008)

From George Schreyer’s Technical Tips 

1. There is a derailment issue with either coupler of the RS-3 pulling a car with truck mounted couplers over turnouts in one particular track geometry. Actually, this problem is not unique to the RS-3 it will happen on any loco with body mounted couplers and limited coupler swing. When the RS-3 runs through the straight path facing point over an LGB 1600 turnout, AND the track curves away from the curved path immediately following the turnout, a derailment will happen nearly every time. As the engine passes the turnout and enters the following curve section, its rear coupler swings the other way. This pushes the coupler on the following car sideways just as the first wheel of the car is running through the frog and the wheel will usually slip sideways and hit the point of the frog dead on and derail. The only fix for this problem is to add at least 6" of straight track (more is better) between the turnout and the following curve. 










2. There is some variability in Aristo-Craft's manufacturing process which results in difficulties in about 25% of the couplers that I have, and I've got quite a few. On some of the units, the knuckle must be pushed in too far before it will latch. If you carefully examine one that works right and one that doesn't, you will see a difference in the latched position of the knuckle. To remedy this situation, disassemble the coupler and grind off about 0.020" from the latching edge on the knuckle, point "A" in Figure 2. 










Another difficulty exists in the shape of the "palm" of the coupler. Some couplers have a small lump where the surface should be fully concave. Use a Dremel tool or round file to grind this area, "B" in Figure 2, back to a smooth concave curve so that the opposing knuckle can full enter to depress and latch the coupler. A good pair of couplers will latch when pressed lightly and there will be a fair amount of slack in a coupled pair. A bad set may not latch at all, or once latched, may be locked tightly together.


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