This pre-20th Century, wooden car was put to a variety of uses by its owners: caboose,
baggage car, railway postal car, and most notably, a baggage-mail combination. Mail transportation
by rail had existed as long as the railroads themselves. In Britain, mail was already being sorted within rail cars in the late 1830's. This practice was imitated on a few American railroads, but came into widespread use only after the Civil War. Perhaps no more efficient mail system could have existed
than that of the railway postal system. Both local and long-distance trains included a car equipped
with pigeonholes, sorting bags and tables, cancellation stamps, and one or more frenzied clerks
trying to sort a bag of mail picked up at one station, before arriving at the next station each would
be only ten or twenty minutes down the road. Early in their history, these railway postal cars (RPO's) shared space with express baggage service. Later, as the system grew more elaborate, entire
60- or 80-foot RPO cars were specially built for that purpose, and resembled small versions of a post office.
    
    As with other aspects of railroading, RPO cars and their clerks have a lore all their own. The metal arms which swung out from the side of the car to catch a hanging mail bag when the train was not scheduled to stop at a station are collectors items, as are any existing cancellation stamps. Clerks carried guns for protection against outlaws wanting to steal the mail. In the first decades, clerks
worked on cars furnished either with fire-causing wood stoves or without any heat at all. Doors could not be left open for security reasons, so the cars were barely ventilated in the summer heat. If they
had toilet facilities at all, they were crude and rarely private. Sometimes a lone clerk, sometimes a handful of men tripping over and stepping on each other, slaved at sorting and canceling mail,
catching a new bag every twenty minutes, and simultaneously kicking off a bag sorted for that stop.
   
     By the 1960's, railway mail, like railway passenger service and some railway freight service, was failing in favor of air transport of mail. The last RPO ran between Washington D. C. and New York in
June 30, 1977.