How is a coupler released? From pictures I can’t see any obvious release mechanism or a handle that says “pull here to release”. Also…I’ve watched switching…a train would back up slowly and then stop…but the last car or two would uncouple and keep rolling…is the engineer somehow able to uncouple cars from the locomotive?
Couplers are uncoupled by a cut bar, which is accesable from the side steps on all railcars and locomotives. When you lift the lever on the bar, it rotates and lifts the pin out of position on the coupler, allowing the knuckle to move. The bar is accesable from the side steps of railcars and locomotives, allowing a brakeman/conductor to “kick” cars by uncoupling them while moving.
If nobody was riding the car (even on the other side) when they let the car roll, then they could have uncoupled when they stopped and shoved the cars with the couplers closed and not coupled, shoving the car forward until the engineer throttled down and the car kept rolling.
Here’s a photo of the cut bar, which is white and has a yellow-ish bar connected to the pin on top of the coupler. It’s circled in red.
I was going to reactivate/ resurrect the ‘‘Knuckle Coupler’’ thread from April- Augsut 2007 shortly anyway, so this is an opportunity to start on that - it’s at -
http://cs.trains.com/trccs/forums/t/93193.aspx?PageIndex=1
- PDN.
Couplers have a locking pin which holds the knuckle in the closed position. The pin is held in place by gravity and is lifted using the “cut lever” to allow the knuckle to turn.
This group of pictures, etc from the San Diego Railroad Museum will probably do a better job of illustrating it than I can.
As for kicking cars (or humping them, for that matter), the brakes can be “bled off” so that a car essentially has no automatic brakes. The handbrake will be used to hold the car if necessary. When kicking cars, the loco does get up a bit of a run, a crewman will pull the cut lever at the appropriate time, and the car will roll on, generally into a line of standing cars. On the hump, gravity provides the “motive power.”
The brakes have to bled off because a car which has its charged trainline suddenly broken (by the parting gladhands) will go into emergency and stop.
I have seen pictures of a locomotive (probably a switcher) which had a pneumatic cylinder on the coupler to lift the pin. That would make it possible for the engineer to handle cars without a second person being necessary to lift the pin.
Houston Ed and Carl can certainly give you a more in-depth picture, since that’s what they do.
Hmm…I can’t seem to find a good picture.
One pulls up on the cut lever, which in turn raises the lock lifter. The lock lifter, lifts the lock, allowing the knuckle to pivot. The action also pushes on the knuckle thrower, which opens the knuckle (sometimes at least).
Normally, once lifted, the lock will stay raised until an impact on the knuckle causes it to fall, thereby locking up the coupler. This feature allows you to kick cars, without having to run next to the car, holding the cut lever up.
Of course if there is no pin holding the knuckle in, it just falls out near your feet.
Nick
Make a fist with both of your hands…then turn the left hand so that the thumb on top and the right hand so that the thumb is on the bottom or vice versa. Now, interlock the two fists placing fingers of one hand inside the fingers of the other hand. That’s the basis for a knuckle coupler. Next, as seen in the pictures, assume the hook or swing portion of the coupler is the outer ends of your fingers with a pin on the pivot. When that pin is “down” the knuckle is closed and tight, but when the pin is pulled up, the swing is realeased and the pair “uncouple”. The pin has a loop atop connected to a bar which extends to the outside of the car on the opposite side of the facing car (facing the car end, that would be to your left); when the bar is lifted, the pin is lifted. When coupling at least one of the couplers has to be “open” then the force of coupling will drop the pin to lock. I hope one can follow this.
One thing not mentioned so far -
The coupler can’t be under significant tension/ pulling when the ‘cut lever’ and pin are attempted to be lifted - such as when a train stops with the slack ‘stretched out’ - the friction from the train force bearing on the coupler’s pin will be too high for that to be accomplished.
So, that’s why more typically the loco will back or push against the car to be uncoupled - even if they’re already rolling in the desired direction - to make sure that ‘slack’ is provided, which is needed to relieve the train forces off of the coupler and its pin so that the pin can then be easily lifted.
- Paul North.
thanks everyone for the excellent responses…
See also the article on ‘‘Couplers - The durable link’’, By Kevin P. Keefe, Published: Monday, May 01, 2006, in the ‘Railroading Reference’, ‘‘ABC’s of Railroading’’, at:
http://www.trains.com/trn/default.aspx?c=a&id=218
which says, in pertinent part, about 1/3 of the way down the page:
‘‘Cars are uncoupled by lifting a lever that reaches from the coupler to the side of the car, making it unnecessary for a switchman to place himself between cars during coupling. Lifting the lever unlocks the knuckle and lets it swing open, allowing the cars to be pulled away from each other.’’
Also note that in the picture Tyler posted there are upward extensions of the cut lever which will allow a crewman to “pull the pin” from the safety of the locomotive steps, even as the locomotive moves away from the car beeing uncoupled. I’ve used this feature many times.
A bit off the subject, but when you see the exciting scene in a movie such as Silver Streak which has the hero uncoupling the train from the engine when the engine is pulling for all it’s worth, you see something impossible unless the train somehow ran forward faster than the engine and thus put enough slack into the coupling.
Johnny
Near impossible as there is always bunching and pulling. But the real element ovelooked is the brake hose which, when parting, would supposedly stop both parts of the train with the second part hopefully not ramming into the first!
Folks here have already covered the basics here very nicely. Most of my railroading career has been connected with uncoupling freight cars.
There used to be a couple of pin-pullers on duty at the top of our hump. Their duty was usually just to pull pins, then line the switches that would send their engine back to the receiving yard for more cars. On a good day, one guy would be making cuts for about 500 cars.
Nowadays the guy not only has to pull the pins, he has to operate his locomotive (via the box), take the engine to the receiving yard, tie it onto the shove, get a ride to the point, line up his route, and ride the shove up to the hump before pulling the pins. Maybe good for 300 cars on a good day, but he’s doing the work performed once by three or four other guys.
The slack doesn’t really have to be bunched for the uncoupling lever to work–it just can’t be stretched. There were many times when I was on the footboard when the engineer would ask me afterwards, “How’d you get that?” These were times when he hadn’t let up on the throttle, but I had nothing better to do than watch the slack.
Pulling pins on the hump sounds easy, but it isn’t just a matter of lifting the right lever as the cars move by. If your cut is for more than one car, you have to go back a little further to get the pin before the slack runs out. Then there’s the problem (sometimes) with the “vertical curve” at the crest–it will cause the couplers to bind against each other, so the cars don’t separate, at least not where they should. My solution to that problem was to stick with the pin–operate the lever once to lift the locking block, then, as the cars began to separate, do it again–hard–to throw the knuckle open as far as possible. It meant that I had to hustle a little more to get back to the next pin, but it also meant that there was a lot less stopping and backing up.
In my current position, a big part of my job is to keep an eye on the pin-puller. If there’s a larger cut of cars, he m
That feature came into use at about the same time that footboards were eliminated, with the locomotive steps redesigned to make it easier for the crew member to stand on the bottom step.
We had one brakeman (at least) who tied a rope to this top extension so he could cut away from a string of cars (or kick them, eventually) without getting out of the cab. For the longest time I thought he was about the laziest s.o.b. on the railroad, but I found out later that he had serious respiratory problems and probably shouldn’t have been on a job like that to begin with (he met his demise one time when he was too far away from an inhaler or a respirator).
In the movie, they uncoupled the F units and first three cars from the rear five cars. If the throttle in the lead locomotive was in run 8 when the train broke in two, wouldn’t that have been enough to keep just two engines (still in run 8) and three cars moving the short distance into the train shed and into the station while the rest of the train comes to a stop near the end of the shed? With the speed the train was moving, I would have thought it possible for that to happen. Granted, uncoupling the train at that speed would be very unlikely, although he did struggle with the uncoupling lever for a while before he got it pulled enough to pull the coupler pin.
Kevin
No tellin’ what really would have happend except know I wouldn’t want to on the train or near the tracks when it did!
.
In the movie they also overlooksd the fact that there was a steam line that would have to be uncoupled as well.
In addition, as soon as the air brake line parted, all of the consist would go into emergency braking. The Pneumatic Control valve in the locomotives’ power circuitry would set the engines back to idle and remove power from the motors. The locomotives would stop quickly and the cars behind (if typical of the disk brake systems the GN used) would stop slowly and the train would not break in two. The train would have stayed together even if the coupler pin is pulled.
Another factor was the speed of the locomotives thru any turnouts at the station would easily derailed the locomotive before hitting the end of track buffer.
Someone mentioned seeing a pneumatic cylinder on a coupler so that the engineer can release it from the cab without a second crew member being needed to pull the pin. That equipment is used by some railroads on helper locomotive sets so that helpers can be uncoupled on the fly without having to stop the train to remove the helper set