It was built by a group of Cleveland, Ohio, electric railway entrepreneurs to serve as a high-speed showpiece line using the most advanced technology of the time.

[1] At the same time, it laid an almost straight double-track route parallel to the Baltimore and Ohio and Pennsylvania railroads, but slightly to the east in less populated territory.

Once onto their own right-of-way, the WB&A's expresses regularly hit 60 mph, but street running in the terminal cities slowed their overall time.

[1] Always looking for new sources of business, the railroad, in 1914, convinced the Southern Maryland Agricultural Fair Association to establish Bowie Race Track along the Main Line.

In September 1917, as the U.S. entered World War I, George Bishop, the WB&A's well-connected president, persuaded the U.S. Army to acquire land owned by the railroad and open a training facility.

The installation was supposed to be a temporary facility, used only for the duration of the war, but it remains in use today as Fort Meade, site of the headquarters of the National Security Agency.

In 1921 it opened a new Washington, DC terminal on New York Avenue and purchased the Baltimore & Annapolis Short Line.

Operations ceased on the B&O track, and a new terminal was built at the southwest corner of South Howard and West Lombard Streets across from what is now 1st Mariner Arena.

Initially, passengers between Baltimore-Washington and Annapolis rode the "classic" 1900-1910 arch-window all-wood-body truss-rod-frame interurban coach.

In the 1920s, when passenger business was good, the line purchased and operated steel two-car articulated (attached body with a common center truck/boogie) coaches on the Baltimore-Annapolis route.

[13][14] The railroad was sold at auction in 1935 and the Main Line and South Shore Divisions was bought by WB&A Realty.

[16] Most of the rest of the main line from the Patapsco River near Pumphrey Station to Washington, DC was sold to the Maryland State Roads Commission in 1941.

[25] While the vast majority of the South Shore division was abandoned and sold for scrap in the 1930s, the portion between Annapolis Junction and Odenton was purchased and operated by the B&O to serve Fort Meade until sometime between 1979 and 1981.

[26] The trains were ferrying riders to and from the United States Naval Academy for graduation ceremonies at the time of the accident.

[29] In 2021, BWRR attempted to take control of a 43-acre parcel of land for its planned station in Baltimore's Westport neighborhood through eminent domain.