FreightWaves Classics: Railway post offices moved the mail across country

The interior of a Railway Post Office prior to 1912. (Photo: USPS Collection)

The interior of a Railway Post Office prior to 1912. (Photo: USPS Collection)


According to the United States Postal Service (USPS), it processes 425.3 million mail pieces each day, 17.7 million each hour, 295,000 each minute and 5,000 each second. Those numbers are staggering, and perhaps more astounding is that 46% of the entire world’s mail volume is processed and delivered by the USPS.

Today, USPS moves mail using airplanes, hovercraft, trains, trucks, cars, boats, ferries, helicopters, subways, bicycles, mules and feet. However, most mail in the United States is shipped via airplane. 

The USPS first experimented with flying mail in 1911 (when it was known as the United States Post Office Department, or USPOD). The USPS negotiates contracts with commercial carriers to transport mail, a practice it began in 1925. Airlines such as United Airlines and TWA began as air mail transporters. 

Earle L. Ovington made the first Post Office Department-authorized mail flight by plane on September 23, 1911, at an aviation meeting on Long Island, New York. He was sworn in by Postmaster General Frank H. Hitchcock. Ovington carried mail on daily flights during the week-long event, carrying mail the three miles between Garden City Estates and the Mineola, New York, Post Office in his Blériot “Queen” monoplane. In this photograph, Ovington can be seen seated above the wings. (Photo: USPS Collection)

USPS has contracts with FedEx, UPS and passenger and cargo airlines to move mail across the nation and internationally. The USPS spent nearly $3 billion to transport mail via air in fiscal year (FY) 2021, which was an increase of about $53 million over FY 2020. These costs consisted of contracted services, commercial airlines, auxiliary transportation, supplemental ad hoc charters, and terminal handling services operations. 

The USPS also relies on its own trucks and contracts with trucking companies to move mail between nearby cities. Trucks generally transport mail that has to be shipped 500 miles or less. 

For longer distances, mail may be transported by freight railroad. A much smaller percentage of mail is moved via ship and to one town in Arizona, by mule train.

Moving mail by rail

The first official movement of mail by rail in the world was performed by the United Kingdom’s General Post Office in November 1830. It utilized adapted railway cars on the Liverpool and Manchester Railway. The first sorting of mail en route also occurred in the United Kingdom in 1838, when the General Post Office introduced the Traveling Post Office on the Grand Junction Railway. 

In the United States, some historians believe that the first shipment of mail carried by train (mail carried in a bag on the train with other baggage) occurred in 1831 on the South Carolina Rail Road. Others refer to the first official contract to carry mail via rail was made between the USPOD and the Baltimore and Ohio Railroad in either 1834 or 1835. That was followed by the designation of all railroads as official postal routes by Congress on July 7, 1838. 

A postal clerk catches mail while also throwing a pouch from the train. (Photo: Illinois Railway Museum)

Railway post offices

President Abraham Lincoln signed the Pacific Railroad Act on July 1, 1862. (To learn more, read this FreightWaves Classics article.) The Act established government funding for the construction of a railroad from the Missouri River to the Pacific Ocean (the transcontinental railroad, which was profiled in this FreightWaves Classics article). A key reason behind the transcontinental railroad was to open a mail route across the western frontier. Language in the legislation stated: “An act to aid in the construction of a railroad and telegraph line from the Missouri River to the Pacific Ocean, and to secure to the government the use of the same for postal, military and other purposes.” The Act authorized government-funded railroad mail routes across the continent.

The railway post office (commonly abbreviated as RPO), was introduced in the United States on July 28, 1862. It was a converted baggage car on the Hannibal and St. Joseph Railroad (which also delivered the first letter to the Pony Express). Purpose-built RPO railcars entered service on the Hannibal and St. Joseph a few weeks after the service began. The mail clerks in the RPOs separated mail in order to connect with a westbound stagecoach that departed soon after the train’s arrival at St. Joseph. The service only lasted for about one year.

An early wooden RPO. (Photo: Iowa Department of Cultural Affairs)

George B. Armstrong

The assistant postmaster in Chicago was George B. Armstrong. He developed the idea of having mail processed and distributed while the mail was on board a train in specialized mail railcars. Schuyler Colfax, Speaker of the U.S. House of Representatives, and A. N. Zevely, Third Assistant Postmaster General, approved, and Armstrong was authorized to test the idea.

Based on Armstrong’s premise, the first experimental RPO route was established on August 28, 1864, between Chicago and Clinton, Iowa. This service was different from the 1862 operation on the Hannibal and St. Joseph Railroad because mail on the permanent route was sorted for and received from each post office along the route, as well as major post offices beyond the route’s end-points.

From the 1870s to the 1950s, railroads were the primary mode of mail transportation in the U.S. To speed delivery, clerks rode in the cars, sorting mail en route. In 1921, due to a rash of train robberies following World War I, Postmaster General Will H. Hays armed railway mail clerks, ordering them to shoot to kill to protect the mail. In 1921 and again in 1926, U.S. Marines were also assigned to guard mail trains. (Photo: USPS Collection)

The Railway Mail Service (RMS) was established in 1869 and Armstrong was promoted and named to head the service as it handled the transportation and sorting of mail aboard trains. RPO railcars operated on U.S. passenger trains to sort mail en route in order to speed delivery of mail between cities. Each RPO was staffed by trained RMS postal clerks; their railcar was off-limits to train passengers. (As seen in many Western movies, armed bandits would often try to rob trains; usually they were seeking to rob the U.S. Mail, because at that time money was often sent by mail.)

As RPOs became commonplace, many railroads earned significant revenue from contracts to carry mail aboard passenger trains. In fact, a number of railroads maintained passenger routes because the financial losses due to too few passengers was more than offset by the transportation of mail.

In Carson City, Nevada, men load mail into RPO #13 of the Virginia & Truckee Railway, which carried mail between Reno and Minden, Nevada, until 1950. Through the early 20th century RPOs were a dangerous place to be on a train – they were of relatively lightweight construction and were located near the front of the train, behind the much-heavier locomotive. Casualties in the railway mail service were high: between 1885 and 1908, 180 clerks were killed and 1,598 were seriously injured. This photograph was taken by Photographer Arthur Rothstein during the five years he spent documenting rural America for the U.S. Farm Security Administration.
(Photo: Library of Congress)

RPOs evolve

RPO railcar interiors first had solid wood furniture and fixtures. However, in 1879, RMS employee Charles R. Harrison developed fixtures that gained widespread use. Harrison designed “hinged, cast-iron fixtures that could be unfolded and set up in a number of configurations to hold mail pouches, racks and a sorting table as needed for specific routes.” In addition, his fixtures could be folded away to provide open space for general baggage and express shipments. Harrison began to manufacture his designs in a factory that he opened in 1881 in Fond du Lac, Wisconsin.

RPO routes were operating on the vast majority of U.S. passenger trains by the 1880s. An intricate network of interconnected routes meant that mail was transported and delivered in a very short time compared to just a few years earlier. RPO railcars (also known as mail cars or postal cars) were equipped and staffed to handle most of the postal processing functions done in a stationary post office. First class mail, magazines and newspapers were sorted, canceled when necessary, and dispatched to post offices in towns along the rail route. Registered mail (which often contained money) was also handled; the RPO foreman was required to carry a pistol while on duty to discourage mail theft.

As many as 10-12 clerks might work in an RPO railcar, although fewer were required if part of the railcar was used to transport previously sorted mail or express and baggage. These railway mail clerks received elaborate training and were periodically tested. On an RPO route, each clerk needed to know the post offices and rail junctions along the route, as well as specific local delivery details within each of the larger cities along the route. 

Employees transfer bags of mail from a truck into RPO #1012 of the Lehigh Valley Railroad, which connected New York City and Buffalo by way of northeastern Pennsylvania and Geneva, New York. All-steel RPO railcars like the one pictured were used as early as 1905 on some lines and grew more numerous following the Steel Car Act of 1912. The USPOD first issued safety specifications to railroad companies for car construction in 1891, following a deadly train wreck at Kipton, Ohio, that claimed the lives of six clerks. (Photo: USPS Collection)

Railcar standardization and safety

Railway mail clerks had one of the toughest jobs in the USPOD, sorting mail on swaying and lurching trains. The clerks’ safety was also of concern. Hazards included oil lamps, coal and wood stoves. Many clerks survived crashes and derailments only to die in fires that swept through railcars from overturned stoves or broken lamps.

To make it easier for the clerks to work on different routes, the RMS adopted standardized floor plans and fixtures for all RPO cars in 1885. The RMS also sought to improve the lighting in the railcars to help the clerks see the addresses on the mail they sorted. Reflectors were improved in the 1880s; oil lamps began bein phased out in the 1890s; and electric lighting began to be used in 1912. 

As passenger railcars developed, so did RPO cars. The initial plans for RPO railcar designs were based on light baggage car frames and bodies. This sometimes resulted in injuries or death for RMS employees when the trains they were working on were involved in accidents. The RMS developed its initial railcar design standards in 1891 to address safety issues. However, from 1900 to 1906, 70 clerks were killed in train wrecks while in an RPO. This led to demands for stronger cars made of steel.

The RMS developed a set of strength requirements for new railcars in 1912. It sought to get the companies that built railcars to use steel for the cars’ major structural components and underframes. 

The RMS revised its safety requirements for railcars in 1938 and then strengthened them again in 1945. Although aluminum was being used in railcars by that time, the RMS banned its use in its railcars’ framing and major structural components. 

A side view of RPO #71 on the Burlington and Missouri River Railroad in Nebraska, with its catcher arm grabbing a pouch of mail from a crane and a mail pouch for local delivery being tossed out. Exchanging mail at small towns without stopping speeded delivery to those communities without disrupting mail schedules between major terminals. (Photo: USPS Collection)

A key feature of most RPO railcars was a hook that was used to snatch a leather or canvas pouch of outgoing mail. These pouches would be hung on a track-side mail crane near the stations of smaller towns where the trains did not stop. With trains often traveling at 70 mph or more, a postal clerk would have a mail pouch ready to be dispatched as the train passed the station. A clerk would swing a catcher arm out to catch a hanging mail pouch while he stood in the open doorway. If there was mail for that particular town, the inbound pouch slammed into the catcher arm while the clerk kicked the outbound mail pouch out of the car. An employee of the local post office would retrieve the pouches and take them to the local post office for delivery.

Bags and parcels wait to be loaded into storage mail cars at the Birmingham, Alabama, Terminal. The improvement of interstate highways and an increase in automobile ownership, along with the growth of the commercial airline industry, led to a decrease in passenger train service in the 1950s and 1960s. With fewer trains running, mail transportation gradually shifted from railroad to highway and skyway. (Photo: USPS Collection)

Passenger trains and RPOs fade

At their peak, more than “4,000 RPO railcars were used on over 9,000 train routes covering more than 200,000 route miles in North America.” Most of this service consisted of one or more railcars attached to passenger trains. However, a number of railroads operated “mail trains” between major cities; these trains often would carry as much as 300 tons of mail daily.

The USPOD began experimenting with a highway version of the RPO in 1941. Highway post office (HPO) vehicles were initially begun to supplement RPO service on routes where passenger train service was not available. However, in the 1950s and 1960s, HPOs often replaced RPO railcars after passenger train service was discontinued on a specific route. 

In 1941, Highway Post Offices (HPOs) made their first appearance when a route was established between Washington, D.C., and Harrisonburg, Virginia, serving more than 20 intermediate post offices. HPOs were similar in function to RPOs and were created in part due to the decline of mail-carrying trains. Like railway mail clerks aboard trains, clerks on board HPOs sorted mail en route for transfer to post offices and connecting routes. The number of HPOs peaked at 172 in 1959. The spread of mechanized mail sorting facilities in the 1960s and 1970s gradually rendered hand-sorting of mail by traveling clerks obsolete. The last HPO rolled between Cincinnati and Cleveland, Ohio, on June 30, 1974. (Photo: USPS Collection)

After 1948, the RPO network began to decline, although it remained the key intercity mail transportation and distribution function within the Post Office. There were 794 RPO routes operating over 161,000 miles of rail in 1948, but only 262 RPO routes were still in operation on January 1st, 1962.

Competition from trucking firms and airlines intensified for the railroads – and RPOs. The Post Office had eliminated many routes by the mid-1960s as railroads severely curtailed or ended their passenger trains due to low ridership and mounting financial losses.

When the USPOD began to process mail at large regional centers, it was sorted by machines, not by people. Remaining RPO and all HPO routes were then phased out. This was followed by the cancellation of all mail by rail contracts in September 1967. Going forward, all first-class mail would be transported by air and other mail and parcels were to be moved by road transport. 

The Post Office’s decision hit the railroad industry very hard. For most railroads, passenger service had not been profitable in decades; they had relied on revenue from the Post Office to cover the cost of their passenger trains.

Clerks sort mail inside an RPO. Railway mail clerks “dressed” RPOs before each run by hanging sacks on the iron racks and then labeling them with the destination post offices along a particular run. Letter-sorting machines, which began appearing in postal facilities in the 1960s, gradually reduced the need for manual sorting of mail, including en route in RPOs. The last RPO route, between New York City and Washington, D.C., was discontinued in 1977. (Photo: USPS Collection)

The RPO legacy

Established by the Post Office Department in 1864 to help facilitate mail delivery over significant distances, the Railway Mail Service was a very reliable service that transported mail across the United States via the railroads. During most of its 113-year existence, the RMS was the fastest way for first-class mail to travel from sender to recipient. 

The New York-Washington route had daily northbound and southbound mail-only trains. By 1977, these were the last such trains operating in the United States. The trains’ final run took place on June 30th, 1977, thus bringing an end to an era.

However, the last run of the name “Railway Post Office” was made by the Boat Railway Post Office in a run over Lake Winnipesaukee between The Weirs and Bear Island in New Hampshire, with a postmark of September 30th, 1978.

An RPO of the Louisville & Nashville Railroad. (Photo: National Park Service)