1 vote

NS - Black Rock Tunnel


Black Rock Tunnel Phoenixville, PA -- October 18, 2008

Overview as two trcks become one looking South

Photo taken by Raymond Klein


BH Photo #157865


The Black Rock Tunnel was constructed between 1835 and 1837 and opened in 1838. W. Hasell Wilson was the resident engineer in charge. The tunnel was originally 1,932 feet (589 m) long, 19 feet (5.8 m) wide, and 17 feet (5.2 m) high.[3] The tunnel passes 122 feet (37 m) below the top of the hill.[1] A, then unique, feature of the tunnel's construction was the sinking of six, 7-foot (2.1 m) diameter shafts, tangent to the tunnel cross section. These shafts were spaced at 100-foot (30 m) intervals to correct errors in the tunnel alignment. Construction of the tunnel cost an estimated $178,992.]

In 1858-9 the Black Rock and Flat Rock Tunnels were widened to accommodate the wider rolling stock from the Lebanon Valley Branch. The spacing between the tracks was increased from 4 feet (1.2 m) to 6 feet (1.8 m). The widening of the tunnel was the first project to employ electric detonation of multiple explosive charges.[6]

The northern end of the tunnel is high on a steep bank of the Schuylkill River so the rail line makes a dramatic transition from tunnel to bridge.

The tunnel was originally two track, but it is now single track.


Tunnel under Black Rock Road on Norfolk Southern Railroad (Former Reading RR)
Phoenixville, Chester County, Pennsylvania
Open to traffic
Built 1838-39, Enlarged 1915, 1994
- W. Hasell Wilson
- Norfolk Southern Railway (NS)
- Reading Railroad (RDG)
Total length: 1,934.0 ft.
Also called
Reading - Black Rock Tunnel
Approximate latitude, longitude
+40.14590, -75.51544   (decimal degrees)
40°08'45" N, 75°30'56" W   (degrees°minutes'seconds")
Approximate UTM coordinates
18/456095/4444078 (zone/easting/northing)
Quadrangle map:
Inventory number
BH 44429 (Bridgehunter.com ID)

Update Log 

  • January 8, 2017: New photo from Dana and Kay Klein
  • October 7, 2014: HAER photos posted by Dave King
  • March 17, 2010: New photo from Raymond Klein
  • March 13, 2010: Added by Raymond Klein


  • Raymond Klein - Bookshelfthe [at] msn [dot] com
  • HAER PA-520 - Philadelphia & Reading Railroad, Black Rock Tunnel, Beneath Black Rock Hill, southwest of Black Rock Dam, Phoenixville, Chester County, PA
  • Dana and Kay Klein