Baltimore-Washington HPO Richard D. L. Fulton The United States Postal Service (USPS) issued a three-cent stamp on February 28, 1952, commemorating the 125th anniversary of the Baltimore & Ohio (B&O) Railroad. The stamp depicted a horse-drawn railcar, the 1829-1930 Tom Thumb, and then-modern diesel. In addition, the legend on the stamps stated, “Baltimore & Ohio…