While looking at my photos of the Esperance ore trains, a question popped in my head. Now they have rotating and non rotating couplers. I get that. But how do the normal ones stay coupled, when they go upside down in the unloader?
As the cars rotate on the same plane as the coupler centreline and one coupler is in effect a round shaft, this allows the 'fixed' coupler to rotate through 170 odd degrees with the car as the rotary coupler does the rotating.
It's a bit like a door hinge, one side is fixed, the other moves.
Also the hose bags, or air lines are normally slightly longer to enable the rotating action. Well the Pilbara has longer hoses anyway.
I may have some snaps at hand.
Okay, here's a pic:
The rotary coupling is on the left, with the fixed or square on the right.
Okay, and here's one at 90 degrees.
Okay, found the images I was looking for.
Here's some shots of the dumper going over.
Thanks for sharing the photo's, explains it nicely, just one question, do they only tip one wagon at a time or do they tip two or more.
Thanks for that Toad. It did satisfy a curiosity, however wasnt the answer i was looking for. I was refering to the coupler unlocking itself when upside down. I have never pulled one apart, but from what i know a block lifts up releasing the knuckle, which i would assume, would fall down when the coupler is upside down, uncoupling. When returned to the normal position in theory if it did fall down (up) when upside down, it should fall back to normal locked position, but it seems unlikely to leave it to chance. Or am i missing something?
Another question is how the uncoupling levers are attached to the rotating coupler. I see a cable in the photo with the coupler at 90 degrees, but how thats usefull i do not know, as the couplers i have seen push up from the bottom to slide the block inside up. I can only assume that the levers are removable and shunters have to carry one, or there is a free one mounted onboard.
Okay, the rotary couplers don't have the 'uncoupling' lever arm.
The cable and clip you see is the 'retainer' that prevents the knuckle from uncoupling unless it's via the lever or fixed end.
The action of the lever is to push up to unlock the knuckle from underneath. On locomotives, it pulls up from above the coupler.
The spring clip attached to the cable you see on the rotary coupler prevents the knuckle from being 'bounced' into the release position. Both the fixed and rotary knuckles are 'locked' in this fashion
A bit clearer now?
i have seen wagons separate after being rotated at esperance but it is very very rare for this to happen these days. i have also seen the result of trying to turn a wagon with 2 fixed couplers coupled together and it usually goes off with a loud bang and is not a pretty sight.
Toad , I will miss your input and photo's when you move out of the pilbra
can't speak for toad's mob or fmg, but rio tip in pairs. wagons are marshalled in pairs with a solid draw bar between.
Only the old robe wagons are done as singles through a different dumper.
Thanks for the information guys. I really appreciate it. Satisfied a curiosity.
BHP Billiton cars have always been single cars. One reason for this is the No. 2 dumper at Nelson Point. which is a triple car dumper, unlike all the others (Nos 1 and 3 at Nelson Point and No 4 on Finucane Island) which are twin car dumpers. The number 2 was the first one built for Mt Newman since the original No 1 dumper came from the Oroville dam in the USA. Not only was no. 2 a triple dumper, but it could dump any of the three cars independently.
To get back to couplers, partly because of the individual cars, Mt Newman cars had fixed couplers that couldn't be coupled to eachother. I think that still applies to BHP Billiton cars.
It is recommended to look-up the web page for McConway & Torley and read about the F coupler (fixed & rotary). Rio Tinto uses the F. The rotary version came out of MIDLAND ROSS back in the 60's who became NATIONAL CASTINGS (NACO) etc to now be a part of AMSTED. Jack Long a friend of mine, did a lot of patent work on the rotary. F couplers have an internal mechanism termed anti-creep or sometimes anti-gravity. This swinging finger moves into place to stop the block lifting during longitudinal train action (snatches or impact causes pitching and thus vertical accelerations at the coupler that can throw the block upwards and thus train un-coupling) or dropping away if up-side down and again a chance of parting when rotated back and dragged forward. Some F rotary couplers have a lever hanging down that can be actuated by manual pushing. Many railways today use uncoupling rods with a key that runs in a slot so that swinging action (from train motion) is restained. To uncouple the rod must be lifted to be rotated. This fails in rotary dumpers and the WAGR WO wagons should have a swinging toggle that blocks the uncoupling rods from trying to rotate. The WO wagons had an E type coupler which was not all that great to say the least.
Thnks for that M636 and Dr. Smith, very helpfull.