Mail pouch for Railway Post Office mail exchange
This cotton mail pouch was used in the Railway Post Office (RPO) “on-the-fly” mail exchange, a service which allowed mail to be transferred between trains and small town post offices while the train was moving. Postmasters placed First-Class mail inside the pouch and closed and secured the pouch with a mail lock. They then placed the pouch on a specially constructed iron crane, securing it to the crane with the rings on both ends of the pouch.
The cranes were placed near train tracks in order to allow RPO cars to exchange mail without stopping. As the train approached, a clerk prepared the catcher arm which would then snatch the incoming mailbag in the blink of an eye. The iron arms of the crane would pop open, releasing the bag to the RPO car. An RPO clerk then booted the outgoing mail out of the train near the crane. Experienced clerks spoke with pride of making the switch at night with nothing but the curves and feel of the track to warn them of an upcoming catch.
Once the pouch was inside the RPO car, a clerk unlocked it and emptied the mail onto a sorting table. Clerks sorted the mail while the train continued to move. Mail addressed to stops along the route were placed into pouches that were kicked off the train as it passed those stops.
Mail on-the-fly officially exchanges ended on May 1, 1971 when AMTRAK began operations. Just prior to the end of the service, thirty RPO trains were still making mail exchanges on-the-fly across the country.