The Rotary Dump ops thread is really helpful (Thanks guys! [:)])… but it’s all about single car dumps. What about ops with gons and hoppers with the rotary couplings? Has anyone managed to model this? (I’d be really impressed)!
On the real thing does the loco shove all the cars into the dump right up to the last car or do they use a barrier car? Come to that… I’m assuming the cars are pushed through… or are they hauled? Is there much dust when the load drops… or are the cars sprayed with water?
I’m not sure if I have the correct answers to your questions, so I’ll offer my opinion!
I don’t know if any model manufacturer makes rotary-style couplers. That would be a challenge to model. I, too, would be very impressed. I have read of several modeled rotary dumpers and all of them operated with one car at a time.
I would imagine the loco shoves the cars into the dumper. One coupler on the end of each car rotates and I think there would have to be slack in the couplers for it to do so.
Dumping coal is messy. Some operations probably do spray water on the coal to reduce the dust, but it won’t eliminate it. I have seen pictures of some rotary dumpers that were fairly well enclosed, probably to keep the dust confined to the dump area.
Someone else may be able to give you more definitive answers and correct me if I am wrong. Hope this helps a bit.
The CNW ore dock in Escanaba Michigan used a rotary dumper, they had a car puller on one end that put the cars in place, and then after they where emptied it pushed them out, CNW usually assinged an SD18 to it. Cars for the dumpers are always pushed, I’m not sure if the dumper can’t handle the wait of a loco, or if its not tall enough.
Most modern rotary dumpers I have seen are along the BNSF(I will reference the one at Alma, WI). The train runs into a large reverse loop and the engines pull the train into the long thaw shed/dumper(it’s cold up here). The train stays coupled and moves forward into the dumper. Once the first coal car is aligned, it is dumped and IIRC, large ‘fingers’ move the train ahead. The engine is sort of ‘creeping’ to assist from what I have been told. The engines are manned. Other types have the train crew do the spotting. The Alma facility has sort of a double track oval with connnection to make it a reverse loop off of the BNSF main track. The train can pull off of the mainline, loop around the oval and enter the dumper, and make another circuit so it stays off of the mainline until it is ready to depart as a empty train. I would guess 2-3 hours between arrival and departure for 100+ cars.
Older power plants have a small stub yard and the unit train is broken up into ‘shoves’ that go through the dumper - So you can have it both ways!
Someone up here in the Niagara Frontier area has done this. He’s built a working model of a rotary car dumper, and built a train of cars with rotating couplers to go with it. I’ve seen it at least twice at NMRA meets or train shows in this neck of the woods. I don’t remember the fellow’s name, unfortunately. It is VERY neat to watch.