The Maryland and Pennsylvania Railroad was formed from two earlier 19th-century 3 ft (914 mm) narrow gauge railways: the Baltimore & Delta Railway, later the Baltimore and Lehigh Railway, and the York and Peach Bottom Railway, later the York Southern Railroad. Construction of the Baltimore & Delta Railway started in 1881, and passenger trains between Baltimore and Towson, Maryland, began on April 17, 1882. Later that year the company was merged into the Maryland Central Railroad. The line was extended northward to Bel Air, Maryland on June 21, 1883, and the following January, the line was completed to Delta, Pennsylvania.