How does the mail get sorted at the post office?

Question

How does the mail get sorted at the post office?

Answer 1

By zip code in auto processing machines. Those piece which  are rejected, are sorted by hand.

Answer 2

Mostly with machines. I have worked there for a few years and I still think its cool to watch.  I work at one of the locations where they sort mail. Most of it is sorted into groups before it gets to our building. There is 3 groups of mail, parcels, letter mail, and flat mail.

  The letter mail is dumped on belts that take it and load it into machines that face it all the same way and then cancel the postage. Then it is put into trays and taken to more machines that sort it. They can be sorted in several ways. The first way is if there is a barcode on the envelope the machine scans the barcode and sorts. The second is that the machines have computers that will try to read the address if there is no barcode. If the machine can't make out the address a picture is sent to a coding facility where a person will read the address on the picture and type it in. Then the machine will spray a barcode on the letter and from that point on it will be sorted by the barcode. The machines also check for change of address and if the address has change the letter will be sent somewhere else to get a label with the new address put on it. They run the mail through the machines in multiple passes. The reason for that is that after it is sorted by location it is put in sequence by house number so that the carrier doesn't have to do anything the letters should be grouped by house in order for the particular route.

   Flat mail is like magazines ant large envelopes. It is very similar to letter mail but has to be run on different machines. We dont have a machine yet that will sort flat mail in sequence, so the carrier has to do that. In 2009 we will have a new machine that will sequence the flat mail.

   Parcels are like boxes and stuff. It is sorted on a huge machine. It is sorted the same as everything else except no barcodes are put on it.

   We also sort some of the mail manually. Not everything we get is machineable.

    Then we got machines that take the mail from the sorting machines out to the loading dock. We have robotic equipment that can stack it in containers. We got machines that store the trays till dispatch time.

    Thats the basic idea anyways. I hope that helps. I work on the machines. I think its cool to watch all the stuff work.