Capital Subdivision

The Capital Subdivision is a railroad line owned and operated by CSX Transportation in the U.S. state of Maryland and the District of Columbia.

[2][3] The northeast end of the line is at Halethorpe, Maryland, (BAA 5.8) just north of the historic Thomas Viaduct, where it meets the Baltimore Terminal Subdivision and the Old Main Line Subdivision.

Its southwest end is at the yard north of Washington Union Station, at a junction with the Metropolitan Subdivision and Amtrak's Northeast Corridor.

In 1831, the Maryland General Assembly authorized the B&O to build a branch from their main line within eight miles (13 km) of Baltimore, to Washington, D.C.[4] As this line would take much business from the parallel turnpikes, especially the Washington and Baltimore Turnpike, the charter specifically allowed those companies to subscribe to the stock of the railroad.

[5]: 361   [6] The first B&O passenger station (1835–1851) was located west of the Capitol, at 2nd Street and Pennsylvania Avenue NW.

Northbound CSX train on the Capital Subdivision at St. Denis
The Thomas Viaduct , built in 1835 over the Patapsco River , was the largest bridge in the United States at that time. It still carries the Capital Subdivision today and is the world's oldest multiple arched stone railroad bridge.
The Thomas Viaduct about 20 years after its construction in 1835
Washington Union Station in Washington, D.C.