Similar but different
Loading a ore boat.
Taconite pellets are much easier to dump than raw iron ore was. Iron ore often has a high moisture content, and can stick together and refuse to go out the bottom of the ore cars. In cold weather, the whole car could freeze into a solid mass. Pellets are like marbles, they just roll out.
It wasn’t clear to me from the video. Once the rotary dumper does its thing, what does that coal fall into? Does it go right onto a routable conveyor belt that takes it to piles or bins, from which that other belt takes it to the ships? I have to assume that the dumper does not move, so since there is finite space under it, the coal has to be kept moving.
Yes - regardless of where it goes, it’ll go by belt in the vast majority of cases. But…
Some ship loading facilities dump(ed) straight into the ship, such as was seen on the ore loading video. Due to the lack of room on many docks, cars would often be dumped singularly, then would roll further onto a kickback arrangement and roll back to the empties track.
I had the privilege of observing flood loading from the loadout control room at a mine in Colstrip, MT a few decades ago. Still ranks as one of the most impressive things I’ve seen.
I thought I had a solid idea of what constitutes a hopper and what constitutes a gondola until Lithonia posed the question. The coal cars BN used extensively in the 70’s and 80’s were obviously gondolas, as they had no capacity to unload from the bottom. Now many of what are called gondolas have the characteristic box shape, but have dump bottoms.
Just to add to the confusion, I do recall seeing coil cars classified as either AAR Class FMS or GBSR, which would make them either flat cars or gondolas.
If you look up the history of the Bethgon, some of the structural and design advantages of bathtub gons can be seen more clearly. Arranging secure-enough lateral drop-bottoms on low-tare highest-capacity aluminum cars is a silly exercise from the beginning unless you explicitly need bottom-dumping … in which case you would buy aluminum hoppers, take the hit in capacity per unit as needed, and keep the ability to put switches on each car to dump continuously (a modernized version of the old Oliver system with the funky truck tires on the cars!)
Many years ago I worked in a coal mine near Pittsburgh - Mathies Mine - and all coal haulage above and below ground was via rail using 20 ton gons. The gons had one rotary coupler and the electric engine, just called a motor, would haul 50 or more cars out to a rotary dumper at a dock on the Monongahela river. The cars would dump into a pit and the coal moved via a conveyer to a barge. The barge then headed up to the coke ovens for off loading. Very effective. Most underground mines used conveyor belts exclusively.
Back in the mid 90s while an engineer for GE in Virginia we did a rebuild of the coal loading system for NS at the Lamberts Point dock. NS cut 2 gons at a time and a gadget called a barney hooked to a steel cable pushed them into a 2 car rotary dumper. Two 100 ton gons were dumped in under a minute if all was working properly. Then conveyers took the coal to waiting ships for dumping into open holds. Really neat.
We had to decommission some existing structure and needed huge diamond cutting saws to remove some truly over-engineered concrete pedestals. Added huge high horsepower electric drives to operate the barney. Very successful project. NS liked it all so much we were asked to automate the conveyers which eliminated most all of the direct dumping into the ships.
Rich
I would have said the same thing, coal hoppers, gons for other stuff not piled high, did not realize there were so many different kind. When I think of a gondola, I remember riding with my parents in an open gon on Q steam trips pulled by #4960. When the gon was at the end of train not as bad, as when it ended up behind the tender on return trips. Could feel the cinders raining down on us as she chuffed along. Dad got one in his eye and Mom got her hankie out and was able to get it out, I wore eyeglasses so never had a problem. Those were fun times for sure, and my memories of a gon.