Supplement to image #26

Formal planning of the Capital Beltway began in 1950 and it was included as part of the Federal Aid Highway Act in 1956 ( image #12 ) even before construction actually commenced in 1957. Although initially known as the Washington Circumferential Highway in planning stages, a number of names were proposed for the highway including Colonial Beltway, Colonial Parkway, Capitol Beltway, and Capital Ring before the designation Capital Beltway was retained in June 1960. The Maryland side of the Beltway was primarily designed by the engineering firm, Michael Baker Corporation.

Built in the winter of 1963, the Capital Beltway Bridge over Cabin John Creek was one of the final sections of road to be constructed prior to the opening of the Maryland side ( I-495 ) in August 1964. The northbound and southbound sides of the bridge are actually separate structures, each of a length of 253 feet, running parallel to each other with only a few inches of space between. The bridge initially comprised a six lane beltway ( three per side ) but was widened, in 1970, to accommodate eight lanes of traffic ( four per side ) in an ongoing effort to expand the capacity of the beltway. The total width of the eight lane bridge is approximately 72 feet.

The bridge has an average daily traffic of 38,000.

Bureau of Public Roads. "Washington and adjacent areas". General Location of National System of Interstate Highways Including All Additional Routes at Urban Areas Designated in September 1955. Cartography by BPR.


Supplement to image #25

Image #25 provides a second view of the Baltimore & Ohio Railroad bridge over the Big Monocacy River. In image #1, the view shown is from between two parallel deck plate girders, upon which the railroad tracks rest. The current photograph shows the interior structure of the deck plate girder systems, two steel I-beams bolted together to form a web. Three of the six stone bridge piers, including that visible in the foreground, were built in the late nineteenth century for a bridge that has since been replaced.

The photograph looks across the river to the west.

Blueprint from Baltimore & Ohio railroad engineering field notes of ICC parties surveying the physical property of railroads, 1914-29. Courtesy of the National Archives, College Park, MD


Supplement to image #24

Image #24 shows the reflection of the Brunswick Bridge. Constructed between 1953 and 1955, the bridge crosses the Potomac River at the location of of Brunswick, MD This city, first laid out in 1780, changed names twice in the nineteenth century. Initially named Berlin by the landowner Leonard Smith, it was renamed Barry in 1832 by the U.S. Postal Service to avoid confusion with another Berlin located in Eastern Maryland. The name was changed to Brunswick by the Baltimore & Ohio Railroad in 1890 to reflect the large number of railroad workers, originally from Brunswick, Germany, who had settled in the city.

With a total length of 2,430 feet, the Brunswick Bridge was constructed as a steel girder and concrete floor beam system linking 18 piers across the river. It is the third bridge constructed across the Potomac in that location. The first was a wood-covered bridge built by the Loudoun and Berlin Bridge Company in circa 1857. It was destroyed by the Confederate army in June 1861, suffering a fate similar to that of the bridge at Point of Rocks ( image #23 ). In 1893 the bridge was rebuilt as an iron through truss bridge on the stone foundations of the previous bridge. This structure was removed after 1953, when a modern bridge was constructed on new piers slightly upstream, as can be seen at the top of the first site plan below.

State of Maryland State Roads Commission, Proposed Bridge over the Potomac River at Brunswick, MD, Plan and Profile, C & O Canal Files, National Capital Parks, National Park Service, Record Group 79. Courtesy of the National Archives, College Park, MD


Supplement to image #23

Completed in circa 1939, the Potomac River Bridge connects the US 15 roadway between Point of Rocks, MD with Leesburg, VA. The plans for the bridge were drawn using a rare camelback through truss design in the months following a great flood of March 19, 1936 that had devastated the town of Points of Rocks.

As seen on the first site plan, below, the piers of the current bridge (spaced 165 feet apart) were constructed on the ruined foundations of a previous bridge. The latter was once a 1360 foot long double-track rail bridge connecting the Baltimore & Ohio Railroad to iron ore mines on the Virginia side of the Potomac. It was built in circa 1850, for approximately $60,000, by the Potomac Iron Company which transported its products on both the Baltimore & Ohio Railroad and Chesapeake & Ohio Canal. In 1861, the original bridge was mined and destroyed by the Confederate army led by Captain Turner Ashby.

State of Maryland State Roads Commission, Plans of Bridge over the Potomac River at Point of Rocks, C & O Canal Files, National Capital Parks, National Park Service, Record Group 79. Courtesy of the National Archives, College Park, MD