Oh look, a post that isn’t bashing a company/Executive by Yours truly [:O]
But anyways, this has been on my mind recently. I know to an extent as to how they unload using a rotary dumper, but other things about it are itching my mind right now. Do they unload them without coupling, and if so do the couplers rotate with the cars?
All of the unloading facilities that I’m aware of DO NOT uncouple the unit trains that are rotary dump.
yes
(Dependent on the type of rotary dump operation, the rotation access is the same as the drawbar/ coupler)
…and then there’s to oops involving locomotives or swapped end cars. (rigid coupled to rigid)
Next time you see a coal or coke train, look at the end of the cars painted, often red, yellow or some such, and that end has a rotary coupler.
Often, the car end is marked on the side “rotary coupler” in the painted area.
Cars with the colored panel end have a rotary coupler. Only one end needs the rotary coupler. The cars swivel on the axis of the couplers. There are cars with rotary couplers on both ends - these are used when coupled next to the engines so they do not have uncouple them to dump the first car(and also at the caboose end when they ran cabooses). Now, they try to arrange the train if possible wit the rotary end next the engines. Of course, mid-train or rear of train DPU power adds to the complications when unloading.
The typical 100-117 car unit coal trains I have seen can be unloaded in 2-3 hours in nice summer weather. Winter operations usually are slower. Many time there is a long ‘thaw’ shed the train runs through just before the dumper house. Large propane or NG heaters thaw out the coal load so that it releases from the car when it is rotated. I have been on several ‘tours’ of these operations and the noise in the dumper house is quite loud.
Jim
[soapbox]And then you have the tale of CN locomotive 8022 in March of 2010 when a purported drunken longshoreman gave it a little spin on the Roberts bank Rotary Dumper! [banghead]
Link to some photos of CN 8022 @
http://princerupertrailimages.blogspot.com/2012/01/roberts-bank-rotary-dumper-mishap.html
here’s a photo of that little coupler hing that MC mentioned as wel CN 8017l:
I used to enjoy looking for the car with rotary couplers on both ends so that the rotary would face the rear towards the caboose or helpers.
I actually still enjoy doing that … 
Looking at the pictures of the tilted locomotive— I’m surpised that the coupler or draft gear didn’t give way. I had no idea they were that strong.
I believe the rotary dumper grabbed the locomotive frame as if it were a coal car in line to be dumped. I can’t imagine a coupler could put up with the lateral/torque forces of moving a ~400,000 lb locomotive in such a way.
I’ve watched the electric arm at NS’s Wheelesburg Terminal pull 60 loads of coal to their rotary dump with relative ease.
It breaks a knuckle pin every now and again and on occasion a knuckle.
Now this is mostly flat ground with a sharp curve going towards the dump.
But they DO NOT turn rotary dump cars at WBT.
Funny,but every once in awhile rotary cars will somehow get turned around and they make it away from the dumping facility undumped .They have to get rounded up eventually and turned on a wye somewhere and placed back in a loaded train to be dumped . [(-D]
I’ve seen as many as 6 pairs of cars ,12 loads all together mixed thru the same train.
In my experience, the cars with double-rotary couplers are somewhere in the middle of the train…it makes no difference where the direction changes, as long as there’s a rotary coupler next to the locomotives at both ends. If there’s not, it’s a safe bet the the DPU will be removed, if the rotary couplers are utilized at all.
We were always cautioned about coupling two rotary couplers together–the whole set could swivel that way, and if the cars were separated they would not tie onto other cars very easily. (Yes, I’ve seen it happen!)
I have seen instances of cars with two rotary couplers being rebuilt with one, and also of a second rotary coupler being added to a car that had had only one.
I have not been in a modern power plant, but you know what? If you had dumpers capable of emptying two cars at once (and you didn’t mind twisting back the paired rotary couplers somehow), it wouldn’t matter which way the cars were facing (there would be times that you could only advance by one car instead of two). But you’d still need the rotary coupler next to the locomotives at either end!
And, is there any color of rotary-coupler end you haven’t seen yet?