The Henryton Tunnel, located near Henryton

Henryton, Maryland

Henryton is an unincorporated community in Carroll County, Maryland, United States.-References:...

 in southern Carroll County

Carroll County, Maryland

Carroll County is a county located in the U.S. state of Maryland. In 2010, its population was 167,134. It was named for Charles Carroll of Carrollton , signer of the American Declaration of Independence. Its county seat is Westminster....

, Maryland

Maryland

Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...

, is the third-oldest tunnel

Tunnel

A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...

 in the world that remains in active railroad use. Constructed by the Baltimore and Ohio

Baltimore and Ohio Railroad

The Baltimore and Ohio Railroad was one of the oldest railroads in the United States and the first common carrier railroad. It came into being mostly because the city of Baltimore wanted to compete with the newly constructed Erie Canal and another canal being proposed by Pennsylvania, which...

 (B&O) Railroad and opened around 1850, it was the first tunnel constructed on the B&O's Old Main Line. In 1865 the tunnel was widened to accommodate double track

Double track

A double track railway usually involves running one track in each direction, compared to a single track railway where trains in both directions share the same track.- Overview :...

. It was rebuilt into its current form in 1903. The tunnel has brick

Brick

A brick is a block of ceramic material used in masonry construction, usually laid using various kinds of mortar. It has been regarded as one of the longest lasting and strongest building materials used throughout history.-History:...

 portals and lining. The coping

Coping (architecture)

Coping , consists of the capping or covering of a wall.A splayed or wedge coping slopes in a single direction; a saddle coping slopes to either side of a central high point....

 and footings are concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

.

External links

• Steve Okonski's B&O RR Photo Tours from Woodstock to Henryton photos of the tunnel and its approaches
• Patapsco Valley State Park