From the days when public transit was clean, economical and efficient: a streetcar post office in Washington, D.C., shown in a photo from the collection of the Library of Congress. The Capital Traction Company (1895-1933) was one of a number of streetcar companies in our nation’s capital.
The U.S. Post Office operated Railway Post Offices (RPOs) on streetcars in many cities, beginning in St. Louis in December of 1892, and including Baltimore (1896), Boston (1895), Brooklyn (1894), Chicago (1895), Cincinnati (1895), Cleveland (1908), New York (1895), Omaha (1910), Philadelphia (1895), Pittsburgh (1898), Rochester (1896), San Francisco (1896), Seattle (1905) and Washington (1896). These moving post offices accepted mail from pedestrians and carried the mail between post office branches, with clerks applying postmarks and sorting on board to speed processing at the main post office.
The increased use of the mail truck led to the decline of street car services. Baltimore was the last city to let the system go, in 1929. For a look at more streetcar post offices and many images of canceled covers (envelopes mailed via streetcar post with RPO cancellations on the stamps) visit here.