in the 1920s, then began a gradual decline with the discontinuance of RPO service on branchlines and secondary routes. After 1942, Highway Post Office (HPO) service was utilized to continue en route sorting after discontinuance of some railway post office operations. As highway mail transportation became more prevalent, the Railway Mail Service was redesignated as the Postal Transportation Service. Abandonment of routes accelerated in the late 1950s and early 1960s, and many of the remaining lines were discontinued in 1967. On June 30, 1974, the Cleveland and Cincinnati highway post office, the last HPO route, was discontinued. The last railway post office operated between New York and Washington, D.C. on June 30, 1977. A large bust and monument to Armstrong is displayed in the north side of Chicago's Loop Station Post Office. Preserved and restored RPO railway cars A restored RPO car is displayed as part of the Pioneer Zephyr at the Chicago's Museum of Science and Industry. The restored 1927 AT&SF Railway #74 RPO car is displayed at the Pacific Southwest Railway Museum in Campo (San Diego County), CA. For the permanent exhibition, Mail by Rail, the Smithsonian National Postal Museum re-created a railway mail train in its Atrium. The interior fixtures are from a de-commissioned mail car. The exterior portion of the Railway Post Office train was created by Smithsonian artisans. Operating divisions – 1950 First Division: Maine, Vermont, New Hampshire, Rhode Island, Connecticut, Massachusetts. Headquarters: Boston, Massachusetts. Second Division: New York, New Jersey. Headquarters: New York City. Third Division: District of Columbia, Virginia, West Virginia, North Carolina. Headquarters: Washington, D.C. Fourth Division: Tennessee, South Carolina, Alabama, Georgia, Florida. Headquarters: Atlanta. Fifth Division: Kentucky, Indiana, Ohio. Headquarters: Cincinnati. Sixth Division: Illinois, Iowa. Headquarters: Chicago. Seventh Division: Missouri, Kansas. Headquarters: St. Louis, Missouri. Eighth Division: California, Nevada, Utah, Arizona. Headquarters: San Francisco. Ninth Division: Michigan, also lines of New York Central Railroad between New York City and Chicago. Headquarters: Cleveland. Tenth Division: North Dakota, South Dakota, Minnesota, Wisconsin, Upper Peninsula of Michigan. Headquarters: St. Paul, Minnesota. Eleventh Division: New Mexico, Texas, Oklahoma. Headquarters: Fort Worth. Twelfth Division: Arkansas, Louisiana, Mississippi. Headquarters: New Orleans. Thirteenth Division: Montana, Idaho, Oregon, Washington. Headquarters: Seattle. Fourteenth Division: Colorado, Wyoming, Nebraska. Headquarters: Omaha. Fifteenth Division: Pennsylvania, Delaware, also lines of Pennsylvania Railroad west of Pittsburgh. Headquarters: Pittsburgh. Effective August 15, 1955, the fifteen divisions of the Postal Transportation Service were eliminated and the mail