The machines USPS is removing from distribution centers can sort more than 36,000 pieces of mail per hour. Here's how they work.

• The United States Postal Service has been deactivating mail-sorting machines around the US ahead of the surge expected from mail-in voting this fall, reports say.
• Each machine can sort up to 36,000 pieces of mail per hour.
• The machines sort letters, postcards, and other mail by bar code.

Mail-sorting machines used by the United States Postal Service (USPS) have been dismantled and removed from distribution centers around the country, according to postal workers. They told Motherboard that at least 19 machines were removed without explanation. An internal USPS letter from June included a plan to remove hundreds of more mail-sorting machines this year.

Postal Workers Union members and some Democratic politicians have expressed concerns about changes to the USPS under Postmaster General Louis DeJoy, a major Trump donor who started his position this summer. President Trump has attacked the USPS and claimed that voting by mail has a high rate of fraud, without evidence.

The USPS has more eyes on it than ever with continued mail-in voting forced by the COVID-19 pandemic. Here's how the sorting machines being removed from distribution centers work.

The machines removed from USPS distribution facilities were delivery barcode sorters (DBCS).

DBCS machine.      USPS

The machines read the barcodes on letters, postcards, and other items of similar size, and sort them.

DBCS machine.      USPS

The USPS says that each machine can sort 36,000 pieces of mail in an hour.

DBCS machine.      Photo by David Ryder/Getty Images

Source: USPS

DBCS is only for letter-sized pieces of mail. Magazines, packages, and other larger items are sorted by separate machines.

DBCS machine.      Photo by Jason Redmond / AFP via Getty Images

To operate most efficiently, a DBCS machine needs two workers: one to input mail into the machine, and one to gather mail after it has been sorted.

DBCS machine.      Photo by JASON REDMOND/AFP via Getty Images

Source: Motherboard

They can run with just one worker, although more slowly.

DBCS machine.      USPS

Postal workers told Motherboard that it's not unusual for sorting machines to be moved between facilities or deactivated when there's less mail volume.

DBCS machine.      USPS

"When you take out one of the machines, it takes away our ability to respond to unforeseen things that may happen," Iowa Postal Workers Union President Kimberly Karol told Motherboard.

DBCS machine.      USPS

Source: Motherboard

While it varies by location, election-related mail is often sorted by hand.

Sorting mail.      USPS

The USPS estimates that it sends more than 142 billion pieces of mail each year, so an election with 250 million ballots wouldn't necessarily overload its capacity if ballots were spread out over a few weeks.

DBCS machine.      Photo by David Ryder/Getty Images

Source: Business Insider