Take the train: collecting U.S. mail with Railway Mail Service markings

Apr 30, 2021, 6 AM

By Janet Klug

One of the most popular topical stamp subjects collected is trains.

Consider that many thousands of people also engage in model railroading or photograph their favorite locomotives. Train enthusiasts enjoy their hobby in many forms.

Train-loving postal history collectors turn their attention to mail that shows evidence of having been carried by rail.

In the United States, the first locomotive ran in Honesdale, Pa., in 1829. In 1832, the U.S. Post Office contracted with some stagecoach and railroad companies to carry mail.

Trains, powered by steam locomotives, were sprouting quickly. The railroads were the fastest and safest way to transport people and goods.

By 1838, all U.S. railroads were designated post routes by the U.S. Post Office Department. This action was the beginning of the Railroad Mail Service. Agents were appointed to handle the mail, assure that the sacks of mail were exchanged properly, and that correct delivery was maintained.

As the post office standardized the handling of mail carried by rail, postal markings indicating carriage by rail began appearing on letters.

Figure 1 shows a stampless letter sent from Cumberland, Md., on Sept. 30, 1843, and to Richard Halton Moale, an attorney. Postage stamps had not yet been issued by the U.S. Post Office Department, so the amount of postage collected is handwritten at the upper right corner.

On this example, that amount was 12½¢, the rate of a single letter traveling between 80 and 150 miles. The sender was Charles Mynn Thruston. Twenty years later, Thruston would be a brigadier general in the Union Army whose orders were to protect the B&O Railroad from falling into the hands of the Confederacy.

The 1850s was a time of rail expansion, with large cities being served by multiple lines. On route maps of the time, some cities look as though they are sitting in the center of a massive spider web.

In 1862, an experiment of sorting and bagging mail in a railroad car led to the formation of Railway Post Offices (RPOs).

Figure 2 shows an 1891 postmark from the Columbus, Midland, and Cincinnati RPO route, typical of the RPO postmarks that can be found from this period.

RPO mail clerks and route agents were employees of the post office who rode the trains and handled the mail. Route agents received, recorded and postmarked mail collected at stations. Railway mail clerks on these mail cars would sort mail received by the route agent and prepare the mail for distribution.

Transfer clerks worked from large transfer stations. They supervised the handling of mail at the depot, the loading and unloading of mail from trains, and assured that a train had sufficient suitable space to contain the mail that would be loaded and carried on the train.

Figure 3 shows a Cincinnati Transfer Clerk postmark dated Dec. 22, 1941. Notice the circular postmark bears the initials "R.M.S.," which stands for Railway Mail Service. The postmark also has a killer that strikes the stamp to invalidate the stamp for further use. Within the bars of the killer are the letters "R.M.S." again.

Figure 4 is a later RPO postmark from the last trip of the Washington & Cincinnati RPO, on Oct. 29, 1967. On this example, the duplex RMS killer can be seen clearly.

For those interested in delving deeper into collecting RPO covers, a great introduction is available on the Smithsonian National Postal Museum's web site at

Excellent books are also helpful, but some of these are no longer in print. Your favorite philatelic library or literature dealer should be able to help you find a reading copy of United States Railroad Postmarks: 1837 to 1861by C.W. Remele, and Railroad Postmarks of the United States 1861 to 1886 by Charles L. Towle and Henry A. Meyer.

The Mobile Post Office Society has a wealth of information available. Contact the MPOS by writing to Douglas N. Clark, Box 427, Marstons Mills, MA 02648; or visit

Mail was carried not just on large, well-known trains. Streetcars in some cities were also converted into mobile post offices and became part of the RPO system.

St. Louis had the first streetcar RPOs. This proved successful enough to extend the idea to an additional 13 cities: Baltimore, Boston, Brooklyn, Chicago, Cincinnati, Cleveland, New York, Philadelphia, Pittsburgh, Rochester, San Francisco, Seattle and Washington D.C.

Figure 5 shows a cropped image of the Brighton Street Car RPO postmark used in Cincinnati on Feb. 21, 1913. The oval barred killer is not very clear, but it contains the distinctive "RMS" indicating that this was part of the Railway Mail Service.

The Mobile Post Office Society has published very useful monographs on the subject of streetcar RPOs.

The Cincinnati, Walnut Hills & Brighton RPO linked several post offices within the Cincinnati area. The route began at the main post office at Fountain Square in the center of the city. It traveled in a clockwise route that over time grew to 14 miles in length and made eight trips each weekday.

The route took the streetcar RPO up and down two of Cincinnati's four inclines, Mount Adams and Fairview, navigating the city's steepest hills. The CWH&B RPO was in service for 20 years, from 1895 to 1915.

If you know someone whose passion is trains, tell them about the Railway Mail Service and watch their eyes light up.