rotary dumper vs use of hopper doors?

[gregc]

i'm curious why early rotary dumpers were used instead of presumably opening the doors on hoppers as they are designed for.

i'm not sure it's fair to compare the economics and insurance issues of today to those pre-WWII when in 1917 the McMyler dumper at Port Reading was built.

my general question is are the doors on hopper cars inadequate for the job or is there more to the MyMyler that made it more economical.

of course the MyMyler dumper is built on a pier and unloads coal into barges.    i believe the issues are different for an entire train that could be pulled through an unloading facility.   so the fact that the McMyler uses gravity to return the car back off the pier is a big benefit.

and how unique was the mcMyler dump in 1917?   while i'm sure it make sense to have them at port facilities, did rotary dumpers make sense in non-pier cases?    how was coal typically unloaded at a power plant at that time?

[riogrande5761]

Just a wild guess, but it may have been significantly faster to unload by rotary than bottom door emptying.  Flood loading also replaced earlier loading methods prob for the same reason.

[ndbprr]

Weather is a big factor. Wet anything in a hopper can freeze into one big lump. It takes quite a long time to thaw out a car.  If you know what you are looking for you will see hoppers with rusty bulges where some rocket scientist heated a car side red hot which of course was not completely effective. But since he doesn't own the car and doesn't care there is no penalty for doing that.  Turn a frozen car upside down and the mass will self break up the frozen load when coming out if the car.  But you need a lot of loads to justify the cost of a rotary dumper and be careful with couplers since most standard hoppers do not have rotary couplers.

[The Milwaukee Road Warrior]

ndbprr

Weather is a big factor. Wet anything in a hopper can freeze into one big lump. It takes quite a long time to thaw out a car.  If you know what you are looking for you will see hoppers with rusty bulges where some rocket scientist heated a car side red hot which of course was not completely effective. But since he doesn't own the car and doesn't care there is no penalty for doing that.  Turn a frozen car upside down and the mass will self break up the frozen load when coming out if the car.  But you need a lot of loads to justify the cost of a rotary dumper and be careful with couplers since most standard hoppers do not have rotary couplers.

 

I bet you are right, especially considering that many types of dumpers seemed to be located in colder climates where it makes sense that materials could freeze in transit.  I'm thinking of taconite pellets up in northern MN, WI, and the UP of MI.  Seem to see more of these dumpers around the great lakes as well.  Consider winter conditions in places like Toledo, Detroit, Cleveland, Buffalo.

[mbinsewi]

There is a foundry in Waupaca, WI., that uses one of these for winter time coke unloading:

http://www.npkce.com/product-categories/hard-car-unloaders/hard-car-unloader/

Thaw sheds were also used:

https://oppdthewire.com/nebraska-city-station-thaw-shed/

Mike.

[rrinker]

 Weather had to certainly be part of it here in our area. Bethlehem Steel had huge thawing sheds to get the iron ore from Cornwall out of the cars. And at the anthracite breakers, they often deliberately sprayed water to keep the dust down. In winter, that whole hopper would be a solid chunk of ice.

 Plus it was just quicker - the hopper doors open fine by gravity, but then someone has to pull them back up to the closed position to secure the latches again. Even in those early days when they had to uncouple each car (no rotary couplers like today). Movies probably don't do it justice - it probably was something to see the now empty car pushed over the edge and up the kickback into the empty car area. 

                                     --Randy

 

[gmpullman]

rrinker

Movies probably don't do it justice - it probably was something to see the now empty car pushed over the edge and up the kickback into the empty car area. 

I remember my dad taking me along on a Sunday "day trip" to the Lorain, Ohio coal dosck to watch the coal unloaders. It was really something to see, especially for a ten year old.

Car_Dumper by Edmund, on Flickr

Somewhere in all my stash of stuff I have a PRR brochure that had the specs for the volumes of coal transloaded in, I believe, the PRR Sandusky coal wharf.

The PRR had trackage rights to move empty hopper cars from Sandusky to Ashtabula, Ohio so you could see PRR trains moving on the New York Central main line.

---

 

gregc

did rotary dumpers make sense in non-pier cases?

I've seen some rotary, or "lift & dump" operations at some steel mills both for coke and ore. The ubiquitous PRR "ore jennies" were solid-bottom cars that required overturning to unload.

gregc

how was coal typically unloaded at a power plant at that time?

Power plants generally didn't need the huge volume of coal to justify the quick unloading. Even if they used six or eight carloads a day it was not needed all at once (as in loading a ship) and one or two cars could be unloaded at a time.

Cheers, Ed

[dehusman]

Rotary may be faster when you include the time it takes to knock off the door locks and then resecure the doors after its empty, compared to the time to clamp the car and rotate it.

[gregc]

considering the issues with ice and need for manual labor to close and latch heavy steel doors, i was wondering if hopper cars were such a great idea.

but despite these issues, they were presumably better than having to manually shovel coal out of gondolas.    And while rotary unloaders make sense at high volume bulk unloading facilities they don't make sense at the myriad of small coal unloading locations such as engine terminals, steel, power, ... plants and local coal dealers.

thanks for the explanations and perspectives

[doctorwayne]

One fairly effective remedy for coal frozen in a hopper car, was to spot the car where it was to be unloaded, then open the hopper door and insert a steam lance.  Of course, this was only possible if there was also a steam plant on-site. 

I have modelled only two small engine terminals on my layout, but do have a small steam plant near one of them.  I haven't yet modelled the overhead pipe system to distribute the steam, but it will eventually be installed.

The other facility doesn't have a modelled steam plant, but it will get a similar system of pipes.

I also have several on-layout coal dealers, but lacking steam plants, they're likely s-o-l with a sledge hammer and a pry bar if a load of frozen coal shows up...

For unloading the coal, the operator simply removes the dump-pit covers, then opens the hopper doors....

This larger facility is able to produce steam for frozen coal loads...

Wayne

 

 

[dehusman]

What is interesting is the evolution of bulk cars.  Originally coal was carried in 4 wheel jimmies that were self clearing hoppers and low side gons.  Then 5-10 ton capy wood truss side self clearing hoppers and drop bottom gons.  To gain more capacity without increasing the physical car size they went to hopper bottom gons.  They had a hopper bottom in the middle by flat gon floors on the ends.  That gave additional volume, but required cleaning out the ends by hand, but not having to shovel over the sides, it could be just pushed to the hopper.  Eventually the hopper came back as a standards as the mines got capacity to handle larger cars with higher sides.  By the 1890's the twin hopper was the default coal car in the east and the drop bottom gon was the default coal car in the west.