Henryton Tunnel

Henryton Tunnel

File:HenrytonTunnel.JPG East entrance to the tunnel. B&O widened the tunnel for double track in 1865, but converted the entire Old Main Line to single track in 1959, to utilize higher center tunnel clearances.
Overview
Line	Old Main Line Subdivision
Location	Henryton, Maryland
Coordinates
System	CSX Transportation
Start	Near Marriottsville, MD
End	Henryton
Operation
Opened	1850
Rebuilt	1865, 1903
Owner	CSX
Traffic	Train
Character	Freight
Technical
Construction	1849-50
Length	430.4 ft (131.2 m)
No. of tracks	1
Track gauge	1,435 mm (4 ft 8 1⁄2 in)
Width	30 ft (9.1 m)

The Henryton Tunnel, located near Henryton in southern Carroll County, Maryland, is the third-oldest tunnel in the world that remains in active railroad use. Constructed by the Baltimore and Ohio (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. It was rebuilt into its current form in 1903. The tunnel has brick portals and lining. The coping and footings are concrete.

See also

• Baltimore and Ohio Railroad
• Industrial Archaeology

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