The Washingtonian was one of two daily American named passenger trains operated by the Baltimore and Ohio Railroad (B&O) during the 1940s–1950s between Baltimore, Maryland and Cleveland, Ohio, via Washington, D. C. and Pittsburgh, Pennsylvania. Inaugurated on April 27, 1941, the Washingtonian was primarily a daytime train with a morning departure, in contrast to B&O's other train on the route, the Cleveland Night Express. Between Pittsburgh and Cleveland, the Washingtonian's cars left B&O rails and were coupled to the Steel King train of the Pittsburgh and Lake Erie Railroad (P&LE) to Youngstown, Ohio, where the Erie Railroad handled the train to Cleveland.
The Washingtonian was the venerable B&O's last passenger train to be powered by steam locomotives on its Washington, D. C. –Cumberland, Maryland mainline, not getting diesel locomotives until April, 1954. Two years later, it was replaced on October 27, 1956 by the faster and more economical Budd Rail Diesel Car (RDC)-equipped Daylight Speedliner between Baltimore and Pittsburgh, reducing operating expenses by half. The streamlined Daylight Speedliner's seven-hour schedule on B&O's Baltimore–Pittsburgh route also trimmed almost two hours travel time compared to the Washingtonian.
In its final year of service, westbound Washingtonian Train # 21 operated on the following schedule (principal stops shown in blue, P&LE–Erie Steel King denoted in yellow):
| City | Departure time |
|---|---|
| Baltimore, Md. (Mount Royal) | 9:00 a.m. |
| Washington, D.C. (Union Station) | 10:05 a.m. |
| Martinsburg, W. Va. | 11:36 a.m. |
| Cumberland, Md. | 1:15 p.m. |
| Connellsville, Pa. | 4:11 p.m. |
| McKeesport, Pa. | 5:12 p.m. |
| Pittsburgh, Pa. (P&LE Station) | 6:05 p.m. |
| Youngstown, Ohio | 7:35 p.m. |
| Cleveland, Ohio (Union Terminal) | 9:00 p.m. |
| source: Official Guide of the Railways, February, 1956 | |