Railway Post Office Cinderella Stamp
A Railway Post Office {RPO} was a special mail car on a train. From the 1860s until the 1950s, most intercity mail in the U.S. was postmarked and sorted by hand en route in these cars. While a train was still in motion, RPO clerks used a long hook to pick up mailbags hung on special track-side poles. The last true RPO made its final trip between Washington D.C. and New York in 1977.
Envelope addressed to Red Cross Founder Clara Barton
The Boston Streetcar RPO picked up this piece of mail, and a clerk postmarked it a 4 a.m. on July 24, 1911. The Boston Circuit RPO ran only at night, collecting and sorting mail from suburban post offices. United States, 1911.
