Providence, RI, was the site of the nation's first automated post office, with equipment created especially for the facility. From that start has come many significant improvements in how the mail is moved. Postal codes (ZIP Codes) were introduced three years after this facility was opened, and nine-digit postal coding was introduced in 1983. Package-handling equipment and conveyor systems have been upgraded substantially. No mail is sorted in transit, as had been the case in the former railway mail system; the burden has fallen to fixed postal facilities.