Coupling Resistance

Model Railroader General Discussion (Model Railroader)
1

I was going to make this comment in the “Free Rolling” thread since it has come up there a couple times, but it’s probably far enough off the original subject to be off topic.

A car’s ability to couple freely rather than be pushed sown the track has more to do with couplers and not as much with weight of the car, grade, and lack of rolling resistance. All of the following is regarding already the exclusive use of Kadee couplers, not knock offs.

With new #148s or other Kadee whisker couplers, or shiny new #5s in centered Kadee draft gear boxes, I can’t MAKE a car roll down a grade without coupling at a decent slow approaching speed. If they don’t couple, it’s the couplers.

Off center: This happens mostly on rolling stock that has screw mounted draft (draught?) gear that can get turned out of center. Not aligned properly, no couple.

Coupler knuckle opening resistance: Somehow the knuckles have gotten gummed up, or even so old that a tiny bit of zinc pest has made them tight. (rare, but I’ve seen it) Painting couplers can do it. If they don’t swing upen freely, they won’t couple consistantly. And delayed uncoupling is impossible.

Knuckle face resistance: If the face of the knuckle isn’t shiny, but dull and flat, that will cause resistance to them slipping freely past each other on coupling. Again zink pest on some oldies contributed, but worse was when I once paiinted some couplers a realistic flat brown. I could push some of them all day until I slam coupled them.

Draft gear boxes: if the centering springs are restricted and the coupler can’t swing laterally correctly and /or recenter properly, in both directions, that’ll do it too. There have been discussions on making Athearn metal clips work better. I’ll add that whisker couplers work better in these than bronze centering spring plates, but NOTHING improves a #5’s behavior better than putting it in a Kadee box with the tapered out bottom p

2

Coupling on curves I can’t help you with, but installing the proper Kadee uncoupling magnet on your test track helps otherwise.

[In HO gauge, Kadee has coupling magnets sized for use with Code 83 and Code 100 rail. If the wrong height magnet is mounted in the wrong track, it doesn’t work.]

Passing a car’s coupler over the magnet shows me if the knuckle opens properly, and if the coupler swings correctly from side to side. Centering capabilities are a visual check.

This is why I won’t allow the club fussbudgets to nip the iron J-shaped coupling pins off of the Kadees – it takes away a testing tool that improves reliability.

3

I have to disagree here. I have had brand new cars, with brand new kadees that will not couple PERIOD. I can increase the locos speed and then they will couple but at SS1 they just won’t. Of course, my Alco S2 runs exceptionally slow. But I’m just saying, this, for me at least, happens for no reason other than the fact that the couplers have more resistance that the wheelsets. The couplers have this resistance for none of the reasons you stated above. They are just like that. Now, I just adapt to these cars and give them an extra bump when I switch them. No big deal.

4

wow, that’s pretty comprehensive.

i’m just curious if a touch of teflon lube on the knuckle face would be helpful in some cases?

5

Graphite or Neolube might adhere better and be less visible than teflon.

6

I have sometimes found that sometimes when the coupler won’t center properly, it’s one of two things especially on couplers that have screw-on covers. Either a whisker has gotten caught under the cover or else the coupler cover is over tightened. And yes, I have done both more times than I care to admit.

I have found this as well when recommended couplers for one car don’t match up to the recommended couplers for another but yet the height gauge says they’re right for the car. Good example: The coupler on the engine for my coal train didn’t match up with the coupler on the coal car. Yet both are “right”. Ended up changing coupler on the engine.

Just my experience as well.

7

Totally agree with your point about the face of the knuckle. A few light, HORIZONTAL swipes with a file will remove the paint on the knuckle and allow much easier coupling. Bonus: I don’t recall ever seeing a prototype knuckle that wasn’t a little shiny.

For the last several years, I have been painting Kadee couplers with no real problems when coupling. The trick, I think, is to use the absolute minimum amount of paint – almost a “dry brush” approach – and very carefully avoid the ‘hinge’ at the coupler’s wrist. It probably helps, too, that I always flex the knuckle several times after the paint has dried.

One thing you didn’t mention is the paint Kadee puts on the part of the coupler that’s inside the draft gear box. I’ve seen some that had very thick paint there. Step 1 for me when installing #5s is to remove all of the paint from all surfaces that wil be inside the draft gear box. This and a tiny squirt of graphite after assembly helps both the self-centering and delayed coupling features.

8

I have found, as I posted in the other thread, that some cars are indeed so free-rolling, that they move if you breathe in the vicinity. These cras, no matmer how much you adjust the couplers, will consistently run away from coupling.

These cars, along with all my Accurail/BB kit cars, all get added weight.

Once the cars weight forces the coupler resistance to no longer be a factor, the issue disappears.

Pease Note: I am in no way stating your tips are incorrect. They are all good to follow.

It’s just sometimes, certain combinations, do not let these tips and asjustments work out enough. In those cases, you need to either -

A: “Slam couple”,

B: Use the 0-5-0 as a holder,

C: Have some kind of “braking” system, be it static grass, pins, axle wipers, etc…

or D: Add weight to the offending cars.

Three of these are not exactly prototypical, one depends on location, and sometimes the most prototypical are harder to do. So, where possible, and all other options are exhausted, add weight. When not feasable, sometimes the less prototypical option(s) are the only option(s).

9

I see the use of graphite recommended as a cure for various coupler problems. I also use graphite to enhance coupler operation but, the method of application I use is different. The good old yellow, No.2 graphite (lead) pencil.

First of all my couplers get brush painted which sometimes “locks” them. Once they have dried hard-at least a week, the knuckle swing is restored by prying it open, and attempting to wobble the knuckle pivot pin in all directions. Once the knuckle opens and closes freely, with spring action alone, using the pencil, all portions of the shank that will contact the draft gear box, are treated with graphite using the pencil in a coloring motion. The knuckle mating face is also treated in the same way.

Graphite is also applied to the upper and lower inside surfaces of the draft gear box, that will contact the coupler shank, especially around the center pin. I have found coupler problems to be nil, not requiring any 40 MPH collisions or chasing runaway cars at 65 MPH.

10

The only coupling resistance problem I have ever had is coupling semi scale couplers to regular original Kadee couplers.

That is one of the reasons I don’t use semi scale couplers.

My cars are very free rolling but I have no problem coupling them gently.

Sheldon

11

Thanks for the input, Gents. Ricky, In my opening statement, I don’t know why I erroniously included weight among things that don’t factor much. I very well know that weight DOES factor in, and add weight to all light cars.[:$]

JJF, your experience is as valid as mine. I should of added the o’l “your milage may vary” caveat.

Chuck, I didn’t mention Kadee’s own paint on them, cuz I’ve never noticed it. I’ll watch for that too, or whatever else may interfere thickness wise.

NHTS, The #2 pencil idea is brilliant! I hope I’m not the last guy in the world to have heard of it, and I’ll try it.

Sheldon, I can’t get good behavior from the semi scaled couplers either, nor do I try after first attempts.

Thanks again, I got new stuff to look for. Dan

12

This. RTR cars out of the box will do this.

13

Do these cars have semi scale couplers? Are they real Kadee couplers? How many brands are actually installing actual Kadee couplers? Do you have a mix of regular head and semi scale head couplers?

The answers to these questions define your problems.

Sheldon

14

Should have said new kadees into new RTR cars. Walthers Proto appears to use kadees though. Metal spring along the knuckle.

Installation is not that complicated.

The problem is the lack of wheel resistance to such a degree that it causes a car to free roll on a 0.25% grade.

Can’t couple on SS1 or SS2. Gotta bang the cars more.

Kadee cars have Kadee couplers installed, of cou

15

[quote user=“Doughless”]

ATLANTIC CENTRAL

Doughless

JDawg

I have to disagree here. I have had brand new cars, with brand new kadees that will not couple PERIOD. I can increase the locos speed and then they will couple but at SS1 they just won’t. Of course, my Alco S2 runs exceptionally slow. But I’m just saying, this, for me at least, happens for no reason other than the fact that the couplers have more resistance that the wheelsets. The couplers have this resistance for none of the reasons you stated above. They are just like that. Now, I just adapt to these cars and give them an extra bump when I switch them. No big deal.

This. RTR cars out of the box will do this.

Do these cars have semi scale couplers? Are they real Kadee couplers? How many brands are actually installing actual Kadee couplers? Do you have a mix of regular head and semi scale head couplers?

The answers to these questions define your problems.

Sheldon

Should have said new kadees into new RTR cars. Walthers Proto appears to use kadees though.

Installation is not that complicated.

The problem is the lack of wheel resistance to such a degree t

16

[quote user=“JDawg”]

Doughless

ATLANTIC CENTRAL

Doughless

JDawg

I have to disagree here. I have had brand new cars, with brand new kadees that will not couple PERIOD. I can increase the locos speed and then they will couple but at SS1 they just won’t. Of course, my Alco S2 runs exceptionally slow. But I’m just saying, this, for me at least, happens for no reason other than the fact that the couplers have more resistance that the wheelsets. The couplers have this resistance for none of the reasons you stated above. They are just like that. Now, I just adapt to these cars and give them an extra bump when I switch them. No big deal.

This. RTR cars out of the box will do this.

Do these cars have semi scale couplers? Are they real Kadee couplers? How many brands are actually installing actual Kadee couplers? Do you have a mix of regular head and semi scale head couplers?

The answers to these questions define your problems.

Sheldon

Should have said new kadees into new RTR cars. Walthers Pro

17

Walthers uses their own Kadee knock off, not genuine Kadees. They brand these Proto metal couplers. They look great but are just a tad inferior to Kadees in practice in my experience. Walthers should just give up and do a deal with Kadee but like other makers they choose not to.

18

I’ve been using Kadee couplers since the mid-'50s, and have used various versions of them over the years, including the semi-scale ones. I don’t have too many issues with coupling, but do agree with your comments on metal wheels, especially the noise factor.

If I buy a car or kit with metal wheels, I do tend to keep them, but I don’t like the racket they make, and I also don’t like the shiny- and overly-wide wheel treads, as they draw one’s eye to that very out-of-scale feature.

Even the narrower “semi-scale” metal wheels don’t look right, as they exaggerate the gap between the face of the wheel and the back of the sideframes.
On real freight cars, the outer face of the trucks’ sideframes are nowhere near the same width as the car-body they’re carrying.

Perhaps if I’d noticed this earlier, I would have opted for Proto 87 standards, but it’s a little too late for me to make that change.

As for free-rolling characteristics, check out this LINK which will take you to the last page-or-so of an otherwise fairly lengthy thread regarding modifying and detailing freight cars. The performance surprised me.

Wayne