A dozen postal workers still sit in a long line at their letter-sorting machines at the Terminal Annex postal station in Los Angeles. Manually they type in ZIP codes and sort about 1,200 pieces of mail an hour - twice as much as with the ''old'' pigeonhole process used until the 1960s.
But an elaborate new creation right next to these workers hums along with the help of just three workers, as it electronically reads ZIP codes, bar-codes their destination on envelopes, and shoots them along a 20-yard channel and into their correct ZIP-code destination slots - at a rate of 10,000 pieces an hour.
Terminal Annex is the first of 118 US postal facilities to plug in the automated equipment, and the first to go public, as Postmaster General William F. Bolger came west to unveil the operation in a press conference here last week.
''We're not claiming any great service improvement with this - but it's going to be there,'' Mr. Bolger said, hedging around those perennial questions that strike at the Postal Service's image of slowness and inefficiency.
The realization of automation - long discussed, and tied to the addition of four digits to ZIP codes - will mean fewer sorting errors, more consistent service, and, most important, a $600 million savings in labor costs alone during the first year of implementation of full automation, Bolger says. The consumer can expect to see that savings reflected in fewer postal rate increases - no rate increases, he says, before March 1984, and none after that until 1987.
(Mr. Bolger stresses that while the bulk of savings from automation will come by cutting labor costs, there will be no layoffs as a result of automation. He says all work-force reductions will be achieved through attrition. And even with increased mail volume expected in years to come, the work force won't have to be expanded because automation will absorb the growth.)
The Postal Service's $316 million automation program is a dual system including optical character readers (OCR) and bar-code sorters (BCS). The OCRs read the address on the face of an envelope, compare the ZIP code with the city and state to verify its accuracy, and convert the ZIP into a series of bar codes that will be ink-jet printed on the lower right corner of the envelope. At the destination post office, the bar codes will be read by a BCS that automatically sorts the letters down to the carrier route level and in some cases down to a particular office building.
Although some OCRs can read handwritten characters, Postal Service automation will apply only to typed, first-class business mail, which accounts for 83 percent of the 370 million pieces of mail processed nationally every day.
The equipment in Los Angeles, manufactured by Pitney Bowes, is being used to read and sort mail bearing the five-digit ZIP code. But starting in October, the machines will be used to process first-class business mail bearing the new nine-digit codes.
''Machinable'' letters, postal officials say, will have to meet these automation requirements:
* At least 33/5 inches by 5 inches, and at least .007 inches thick.
* A maximum of 61/8 inches by 111/2 inches, and 1/4-inch thick.
* Proper address format, including the correct ZIP code and plain typefaces. The bottom line of the address must include - all on one line - the city, state, and ZIP code.
A half-cent-a-piece discount for OCR-readable mail with the nine-digit code has been requested by the Postal Service, and is expected to be approved by the time the nine-digit codes go into effect in October, Bolger says.