Knuckle Coupler

if it has an E or an F on it will tell you what type of knucke it is... other then that... your guess is as good as mine....

csx engineer 

I see "AAR", somthing that might be "(?)3", "ASF", "(?)G6(?)", "H(T?)", and "A" in an octagon.  If there a single E or F on it it's not visible in the pictures I took.

Where would the E or F appear? 

cvt 

Randy Stahl wrote:

You can tell if it's an E or an F knuckle . No way to date it. R

Even if you offer to take it to a fancy restaurant?

ericsp wrote:

Randy Stahl wrote: You can tell if it's an E or an F knuckle . No way to date it. R Even if you offer to take it to a fancy restaurant?

Mookie wrote:

ericsp wrote:  Randy Stahl wrote: You can tell if it's an E or an F knuckle . No way to date it. R Even if you offer to take it to a fancy restaurant? Eric - Poo.....

Date a knucklehead and pretend he's a knuckle coupler.

Dave Nelson

.....On the subject of Knuckle coupler....and a bit off topic...Can someone in clear terms describe how the force is transmitted thru these couplers.  I look at the connection and see a hinged piece on each that fits together when coupled but for the life of me, can't see just what takes all that force...Tension and compression, applied thru it by the loaded consist. 

.....That's partly my point....That insignificant pin can't possibly take any of the massive force coming through the coupler.  Those two hinged pieces must in some way wedge together to make a "solid" block connection within the coupler casting to take the load....But I sure am not certain in anyway that is what happens.

jchnhtfd wrote:

Amazing, isn't it?  That insignificant little pin does take some of the draft force, but not very much because of the leverage involved.  Almost all of the force goes through the hinge pin instead, on which the outer part of the knuckle pivots to open and close.  This hinge pin, which doesn't look all that robust either, is loaded in what engineer's (the PE kind, not the real kind) refer to as double shear rather than bending, and really is strong enough.  Believe it or not...

In fact you can run a train normally with the knuckle pin completly gone, all that pin does is holds the knuckle in when it opens . One good thing to teach new guys is to stand clear of the knuckles in case the pin is broken or missing , causing the knuckle to drop out onto a foot !!

The actual draft pin is well inside the coupler , it drops down and acts as a wedge that fits between the knuckle and the draft head.

I will gladly furnish a knuckle to anyone who wants to buy an expensive dinner for one .. as long as I get to watch you lug it in to the restaurant !!!

....Anyone else out there care to give a discription of how force is carried through one railroad coupler to the connecting mate.....I've checked photos in Google, etc....but still don't see the path the force is carried through the assembly. 

Modelcar wrote:

....Anyone else out there care to give a discription of how force is carried through one railroad coupler to the connecting mate.....I've checked photos in Google, etc....but still don't see the path the force is carried through the assembly.

I probably won't get my hands on a coupler for a month or better...  I do see a groove in the knuckle - might be a factor.

Randy Stahl wrote:

I will gladly furnish a knuckle to anyone who wants to buy an expensive dinner for one .. as long as I get to watch you lug it in to the restaurant !!!

Geez, Randy, doesn't the world have enough knuckle draggers already without your offer? 

And no, I am not referring to conductors dealing with break-in-two situations, as I believe the protocol explained on the forum is to drop a good knuckle off of one of the units, pull the front half forward and then rest the good knuckle on some convenient surface as the cars are shoved back to the rest of the train, then wrestle the exchange there.  Not much knuckle dragging there, at least.  Still doesn't sound like fun to me, which is why I was a PE type engineer, instead of the railroad flavor.  (Still registered, just in case.)

....Thanks Tree.....I'll keep looking for more illustrative photos and maybe I'll finally get to understand the mechanics of it.  It just seems one aspect of the mechanics of railroading I can't get a handle on to understand. 

Modelcar wrote:

....Anyone else out there care to give a discription of how force is carried through one railroad coupler to the connecting mate.....I've checked photos in Google, etc....but still don't see the path the force is carried through the assembly.

That is an interesting question.  I have certainly opened and closed a lot of couplers, but I could not draw an accurate picture from memory of what goes on between the knuckle and the coupler pin.  I do know that the whole coupler disassembles like a puzzle.  Like most mechanical devices that have been used and perfected over a long period of time, the automatic railroad coupler strikes me as a truly elegant work of art.  It ranks right up there with the freight car truck.

I always admired the way you could pull the pin and it would hold that released state on its own, as well as the way you could open the knuckle by pulling the pin if you pull it fast and hard.  And I always wondered why some pins, especially the top-pull pins, would sometimes fail to hold the pulled state on their own.  Was it a matter of internal wear?

Someone pointed out above, that the knuckle pin merely serves to hold the knuckle in place when it is open and disengaged from the coupler pin, as well as the convincing hazard of pulling the coupler pin when the knuckle pin is missing, grabbing the knuckle to open it, and having it fall on your toe. 

I had never thought about this issue of the knuckle pin's function before.  I guess I always assumed that it was part of the load carrying mechanism.  Is it true that a pair of mated couplers with the coupler pins locked, could transmit the pulling load with their knuckle pins missing?  I could see this being possible, if the coupler pins locked in such a way as to prevent the knuckle from pulling lengthwise as well as from rotating in its open/close path.  However, it would seem that if this is the case, the knuckle pin needs to have a sloppy enough fit to prevent it from sharing any of the load with the coupler pin.

Surly there must be a clearly drawn diagram of the parts and functions of the automatic coupler that someone could find and post.  I don't recall seeing this matter thoroughly explained and illustrated in any of several hundred railroad publications, however.

It's called a "Janney" coupler.  We still use it with only very minor improvements.  This is what I found:

The following extracts comes from United States Supreme Court decision - Norfolk & Western Railway Co. v. Hiles (95-6), 516 U.S. 400 (1996) and provides historical background and development of the automatic car coupler:

Railroad Car Couplers
Railroad cars in a train are connected by couplers located at both ends of each car. A coupler consists of a knuckle joined to the end of a drawbar, which itself is fastened to a housing mechanism on the car. A knuckle is a clamp that interlocks with its mate, just as two cupped hands--placed palms together with the fingertips pointing in opposite directions--interlock when the fingers are curled. When cars come together, the open knuckle on one car engages a closed knuckle on the other car, automatically coupling the cars. The drawbar extends the knuckle out from the end of the car and is designed to pivot in its housing, allowing the knuckled end some lateral play to prevent moving cars from derailing on a curved track.

For most of the nineteenth century, the link and pin coupler was the standard coupler used to hook together freight cars. It consisted of a tubelike body that received an oblong link. During coupling, a railworker had to stand between the cars as they came together and guide the link into the coupler pocket. Once the cars were joined, the employee inserted a pin into a hole a few inches from the end of the tube to hold the link in place. The link and pin coupler, though widely used, ultimately proved unsatisfactory...

Janney Coupler
In 1873, Eli H. Janney patented a knuckle style coupler that was to become the standard for the freightcar couplers used even today. [*1]. The coupler had a bifurcated drawhead and a revolving hook, which, when brought in contact with another coupler, would automatically interlock with its mate.

The Janney coupler had several advantages over link and pin couplers. Not only did it alleviate the problem of loose parts that plagued the link and pin coupler, [*2] it also allowed railworkers to couple and uncouple cars without having to go between the cars to guide the link and set the pin. [*3] One commentator described the automatic coupling operation as follows:

 While the cars were apart, the brakeman had to make sure the knuckle of the coupler on the waiting car stood in an open position and that the pin had been lifted into its set position. When the opposite coupler was closed and locked in position, the brakeman was able to stand safely out of the way and signal the engineer to move the cars together. When the knuckle of the coupler of the moving car hit the lever arm of the revolving knuckle on the open coupler, it revolved around the locked one, while concurrently the locking pin dropped automatically from its set position into the coupler, locking the knuckle in place. Although the brakeman had to set up the entire situation by hand, the actual locking operation was automatic and did not require the brakeman to stand between the cars."

Though the market was flooded with literally thousands of patented couplers, [*4] Janney's design was clearly among the best and slowly achieved recognition in the industry. In 1888, the Master Car Builders Association Executive Committee obtained a limited waiver of patent rights--placing much of Janney's design in the public domain--and adopted the design as its standard.

In 1875, there were more than 900 car coupler patents. By 1887, the number of coupler patents had topped 4,000, and by 1900 approximately 8,000 coupler patents had been issued.

1 Janney was a dry goods clerk and former Confederate Army officer from Alexandria, Virginia, who used his lunch hours to whittle from wood an alternative to the link and pin coupler. F. Wilner, Safety: "A great investment," Railway Age, Mar. 1993, p. 53.

2 Automatic couplers also made possible the use of power air brakes, which had not been successfully used with link and pin couplers because of excessive slack in the coupling.

3 Ezra Miller is generally credited with creating the first semiautomatic coupling device for passenger cars--known as the Miller Hook--but it was never widely used on freight cars. C. Clark, Development of the Semiautomatic Freight Car Coupler, 1863-1893, 13 Technology and Culture 170, 180-182 (1972).

4 In 1875, there were more than 900 car coupler patents. By 1887, the number of coupler patents had topped 4,000, ibid., and by 1900 approximately 8,000 coupler patents had been issued. Clark 179.

To Bucyrus and tangerine-jack, thanks for your illustrations of coupler operations and info....I'm gaining on it....

It is common knowledge that the modern automatic coupler replaced the old link and pin coupler.  However, there must have been hundreds of variations of both types that achieved practical application, not to mention the hundreds of other designs that were patented and tested.  This was especially true with the link and pin coupler since it came to be viewed as a problem that needed fixing.  There were several attempts to automate the link and pin couplers. 

John White's book The American Railroad Freight Car has an extensive discussion of the evolution of coupler design including many fine engraving illustrations.  However, I do not see such an illustration of the current coupler design.  It has evolved quite far from the original Janney design.

The problem with link and pin couplers is widely understood to have been the hazard of standing between the cars to hold the link up as the coupler faces came together.  This is sort of like putting you hand into a punch press and removing it at the last second.  And even if you removed your hand in time, the couplers could deflect and pass each other, thus allowing the cars to come together against their dead blocks.  So a brakeman could remove his hand in time, only to have his body crushed by the car ends.

But aside from the safety hazard, another significant problem of the link and pin couplers were the detachable parts, and the variation of these parts that made them non-interchangeable.  Mr. White points out that road crews would hoard pins and links in a stockpile in their caboose so they would be prepared to meet any contingency of missing hardware on cars that they were to pick up.  Of course, in order to maintain their stockpile, they would often strip all the links and pins off of cars they set out, leaving the next crew to refurnish the hardware from their own stockpile.

the archeologists at Golden Spike NHS have found both broken pins and broken links on the 2.2% grade from Blue Creek to Promentory.  How would it feel to be a brakeman in the caboose and noticing the change from forward motion up the grade to reverse motion down the grade - knowing there is a sharp hairpin curve on a fill at the bottom?

The knuckle coupler was a great step forward in RR safety in more ways than one.

dd

....If the caboose suddenly stopped and started to slip backwards down grade, I'd imagine the inhabitants would scramble to get outside to the "porch" and wind quickly on the brake wheel....!

This thread reminded me of an interesting discussion/argument that was going on in the MR forum a while back:

www.trains.com/trccs/forums/1053198/ShowPost.aspx

el-capitan wrote:

This thread reminded me of an interesting discussion/argument that was going on in the MR forum a while back:www.trains.com/trccs/forums/1053198/ShowPost.aspx

And I thought we got contentious from time to time....

Different, but same. 

 I haven't yet found anything as far as a technical paper or some other factually based document that describes the forces that act upon a coupler.  I know that somewhere there is a document that states the information to answer the original question modelcar asked.  I assume we all agree how and why a coupler works and the evolution thereof, but where and how is the stress distributed within that coupler?  I will continue searching, maybe this weekend I can shoot by the library and take a look at some tech info.

Good thread BTW.  I was not aware that I didn't know this information.  Now I can find the knowledge to correct my ignorance of the subject.  Thanks!

el-capitan wrote:

This thread reminded me of an interesting discussion/argument that was going on in the MR forum a while back: www.trains.com/trccs/forums/1053198/ShowPost.aspx

Pretty dull reading actually , is it a pin , or is it a lock , or does it really matter ....Bend the iron .. pull the pin .... what ever ...

Found as in found. The RR is defunt, line was abandoned.

Pick it up? Your joking, right?

My tractor drug it out o' the weeds! And yes that took a bit of grunt.

cvt