Built in 1924 in Saint Charles, Missouri, for the Colorado & Southern to deliver the mail. During the 19th century, the United States Postal Service operated by mail, getting sorted at the post office and sorted into bags, which were then transported by horse or train to other post offices and onto their final destinations. George Armstrong was the Post manager in Chicago. He invented the ability to have mail sorted on the train as it was en route. Illinois at the time. This was so the mail pouches were ready to go when the mail arrived at the destination city. The Chicago & Northwestern Railroad was the first to serve the Railway Mail Service in 1864 and was inaugurated in 1869. The United States had 6 operating divisions. Each of these divisions had a superintendent. Armstrong was the General Manager for the Railway Mail Service. In 1913, the postal service started delivering parcels, which led to terminal railway post offices in major cities that had a high volume of mail services reaching their peak in the 1920s. Colorado & Southern Railway Post Office 254 served between Montana and Texas. Its biggest competitor was the Chicago, Burlington & Quincy Railroad. However, automobiles and commercial aviation took over transporting mail, which made the railroads lose business slowly, starting on branch lines and secondary routes, and then many other routes were abandoned up to 1967. Passenger routes were also getting discontinued during this time. Colorado & Southern Railway Post Office 254 was donated to the Colorado Railroad Museum in 1968. The last run of the Railway Post Office was from New York to Washington, DC in 1977.