The Ma and Pa was popular with railfans in the 1930s and 1940s for its antique equipment and curving, picturesque right-of-way through the hills of rural Maryland and Pennsylvania.

The railway's Middle Division laid narrow gauge track between York and Red Lion by August 1874 and completed its line southward to Delta in 1876.

Because of their narrow gauge construction, the Baltimore and Lehigh Railway and York Southern Railroad could not interchange freight cars with other lines.

[2] The two companies finally converted to standard gauge between 1898–1900 and subsequently merged to form the Maryland and Pennsylvania Railroad on February 12, 1901.

[2] Particularly on the Pennsylvania Division (Delta–York), slate from Delta and manufactured goods from Red Lion and York were mainstays of the railroad's outbound freight traffic.

On the Maryland Division, inbound anthracite coal deliveries accounted for a significant volume of car loadings, along with milk from the many dairy farms in the area.

Carload freight volume increased in the 1920s, however, as more industries appeared along the line, and earnings were strong enough for the company to declare dividends in 1930 and 1931.

[4]: 111  This period of relative prosperity ended during the Great Depression; the railroad's gross revenues fell by half from 1932 to 1935.

[4]: 114 In the mid-1930s, the Ma and Pa became a favorite of railfans, who were attracted to its hilly, curving line through rural Maryland and Pennsylvania.

[7] Following the end of World War II, the Ma and Pa acquired four diesel locomotives for more efficient operations, but traffic declined significantly.

[9] In the 1960s, the Ma and Pa Railroad continued to solicit business along its line for its remaining 34.8-mile (56.0 km) Whiteford–York segment, almost entirely in Pennsylvania.

[3][5] Founded by enthusiasts and former employees in 1986, the group has restored the Muddy Creek Forks station and maintains a small collection of rolling stock there.