Letters, magazines and packages from more than 700 ZIP codes come streaming through the facility's loading dock every day. Most of them are on their way within 24 hours, and all of them are back out the door within three days.
The Charleston Processing and Distribution Center is the epicenter of the U.S. Postal Service's operations in the region. The plant handles mail for nearly all of West Virginia and a sizable portion of Kentucky, including Ashland and Pikeville.
Covering more than two football fields and fully employing around 538 people in three shifts, the center is an emblem of the modern-day postal system.
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It's centers like this one, located behind Cabela's on Corridor G, that still enable the Postal Service to send letters for less than 50 cents and ship packages anywhere in the country for just a few dollars. And right now, the facility's managers and staff are gearing up for their busiest time of the year.
The holiday season is by far the most strenuous time for the center. The number of packages the facility handles increases by 24 percent to 26 percent. The number of letters sorted jumps from around 500,000 a day to more than 800,000.
"If you see red and green it's usually Christmas cards," said Sherry Cox, an administrative assistant at the center, as a machine spit out letters based on their street address.
In order to keep up with that growth over the next couple weeks, the center has hired another 72 seasonal workers to help unload the incoming trucks and staff positions at sorting machines throughout the center.
But as Cox explains, finding someone to fill those positions isn't always easy. The center had to interview hundreds of applications to find enough workers this year, and already several have dropped out - some of them underestimating the amount of labor that goes into getting the mail to people on time.
"This job is not for the faint of heart," Cox said, as full-time and seasonal workers hurried to get that night's deliveries sorted and packaged for their next destination.
Even without the onslaught of Christmas cards and holiday packages, the center is always being tested, pushed to achieve perfection at a Sisyphean task.
"It's a lot more than just Christmas here," Cox said, adding that the facility handles everything from dolls to grandpa's medicine from the Veterans Administration.
While first-class mail - letters - have dropped off due to things like email and electronic billing, Cox said the number of parcels - small packages - that the facility, and the postal system in general, handles has increased dramatically due to online shopping.
At the same time, the center has had to keep up with the shrinking number of locations handling mail in the region. As the Postal Service has moved to streamline its operations in recent years, some processing centers, like Charleston's, have been called on to pick up the slack.
"The building has stayed the same, but the mail has gotten much, much larger," said Wendy Hall, a transportation manager at the center.
In recent years, consolidations in the Postal Service have forced the center to take on work that had previously been handled in Huntington, Beckley, Bluefield, Parkersburg and Clarksburg. As a result, the number of automated letter sorters at the center has increased from eight machines in 2011 up to 23 today.
To handle the increased workload, the center has become more mechanized since it got its start in 1991. Cox said more than 96 percent of the processing work performed at the center is now automated, with advanced machines replacing what hundreds of workers used to do.
"All of this used to be done manually," said Cox, who started with the postal service 34 years ago as a mail carrier in Elkview. "Every year we increase our automation, our speed, our accuracy."
Throughout the sprawling processing center, there are specialized machines capable of processing thousands of letters and sorting hundreds of packages in minutes.
"This machine, it's our instigator," Cox said, as an employee flipped a dumpster sized container of letters onto a conveyor belt. "It starts the whole process."
The machine separates the letters, automatically reading a varied assortment of handwriting styles, deciphering ZIP codes and street addresses in milliseconds, and stamping the letter with unique barcode. All the while, it sniffs the mail, checking for things like anthrax.
From there, the letters are sent whirling through an overhead vacuum-powered transportation system, until they reach another machine that can sort the letters down to the order the mail carrier delivers them on each street.
A similar machine makes sure readers all over West Virginia and Kentucky get their latest edition of Sports Illustrated and Cosmopolitan on time. And another makes it possible for that Amazon Prime delivery to show up in the promised two days.
The facility replicates that process 24 hours a day, seven days a week. When one of the center's intricate processing machines need to be serviced, the plant has backup equipment capable of handling the load.
Even when the 2012 derecho shut down power at the facility for a couple days, Cox said there were workers at the plant attempting to sort mail by hand, using headlamps to light their way around the massive facility.
"We don't close down," Cox said. "There's no day we're closed."
The facility is like a city in and of itself, complete with its own highway system. Motorized forklifts and carts towing baskets of mail zip down boulevards lined with conveyor belts and mail "gurneys" that look like large laundry carts.
A visitor to the center would be wise to look twice before crossing one of these roadways. The drivers are talented, operating the machines as fluidly as if it were a part of their own body, but they move with the speed needed to process the huge influx of mail that arrives every day.
In one corner of the center on a recent Friday evening, a mountain of packages were piled onto plastic pallets, a seemingly insurmountable amount of work. That mountain, Cox said, would be gone by the next morning.
"It's a big puzzle, and it doesn't work if things don't go the right way," Cox said. "It's an interlocking chain and everything has to be coordinated."
Reach Andrew Brown at andrew.brown@wvgazettemail.com, 304-348-4814 or follow @Andy_Ed_Brown on Twitter