Here's some info I've had around for a few years. Came from one of the freight car forums. A former CNW sales guy who had a tire plant in Des Moines as part of his territory provided this on Carbon Black:
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Carbon Black -- It's made in many grades and is used as a reinforcing
and pigmenting agent for the tires. There were many origins for
this: Deguassa had plants in Belpre, OH & New Iberia, LA; Sid
Richardson had plants in Borger, TX, Addis, LA & Big Spring, TX;
Columbian had a plant in El Dorado, AR (?), Cabot in Tate Cove, LA
and Aransas Pass, TX. For a current list of carbon black plants, try
www.chemexpo.com/news/PROFILE000529.cfm. There were other minor
suppliers to the Des Moines plants but the ones I listed were the
ones who were the major players. Each plant would always order
product from several suppliers. In nearly all cases, the cars were
relatively small, specialty covered hoppers owned or leased by the
shipper. They were always black covered hoppers but came in a wide
variety of sizes. For example, I see in the listing that Sid
Richardson's were marked SRCX and came in 50, 55, 70, 77, 79.5 and
80.5 ton capacities. The fun part was that you had to come up with
individual rates to charge for each size car, but that's a discussion
for another time. One of the big problems that the shippers had was
controlling their private car fleets. The tire plants just love
to hang on to the shipper's cars for weeks on end, at no charge. The
reason is that the carbon black comes in many grades and the plant
will choose to unload only part of one car, then part of another car,
etc, as they mix and match the various "black" grades for the type of
tire compound that they happen to be producing. The plants didn't
normally store much of the carbon black in their own storage
facilities but used the RR cars since it was easier (an cheaper) to
use the cars for storage. So, if modeling, you need storage tracks
in and around tire plants to use as "parking" for the carbon black
cars that always sit around. You'll also need to be spotting and
pulling cars to and from the unloading area per the plant's specific
requests each day. For example, you may have 10 cars on hand, and
they'll ask for SRCX 1350 to be spotted from storage to "spot 1" and
CCX 602 to "spot 2" for unloading and pull SRCX 1207 and hold it
(partially unloaded) and pull SRCX 1357 empty, return route to
Borger, TX. So, the instructions could be much more complex than
just "spot in the loaded car / pull out the empty" each day. In
terms of volume, there wasn't quite as much carbon black moving to
the plants vs. rubber (in terms of cars/year) but it always seemed
like there was more carbon black since there were always cars sitting
around. Also, unlike carbon black plants where all of the cars would
tend to be marked the same (SRCX, etc), tire plants would typically
have a variety of cars of different types from several (usually 3-4)
different suppliers.
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Modern CB cars also have relatively small hatches on top, and lots of them. The cars are also pretty tall - comparable to hi-cube clearances. I'd like to see an N scale version of the recent HO scale Rail Shops CB hopper too. Eventually my layout will model it's way to Akron, OH so CB hoppers are a must have for me.
I understand Eric Neubauer did a book covering Carbon Black Cars - Freight Cars Journal Monograph #15. Has anyone seen a copy? Also MM and RMC have had articles covering the older cars. I have the issue Mo/Yr in case anyone is interested.
Steve
