Mount Washington Transit Tunnel

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Mount Washington Transit Tunnel
August 2009 Mount Washington Tunnel.jpg
North portal to the tunnel
Location Pittsburgh, Pennsylvania, U.S.A.
Status operational
System Pittsburgh Light Rail
Start Station Square
End South Hills Junction
Work begun October 6, 1902
Opened December 1, 1904
Operator Port Authority of Allegheny County
Length 3,500 feet (1,100 m)[1]
No. of tracks 2
Track gauge 5 ft 2 12 in (1,588 mm)
Electrified 1909
Grade 6%

Mount Washington Transit Tunnel is an important public transportation link in Pittsburgh, Pennsylvania, United States. The approximately 3,500-foot (1,100 m)[1] tunnel connects Station Square to South Hills Junction, and is used only by Pittsburgh Light Rail cars and buses of the Port Authority of Allegheny County.


The tunnel was built by Booth and Flinn, as a replacement for the Pittsburgh and Castle Shannon Tunnel, but at a lower elevation. Excavation was started October 6, 1902, and the tunnel was officially opened December 1, 1904, for use by trolleys/streetcars only. Originally, steam powered trains ran through the tunnel, to be replaced by the first electric cars in 1909. It took over the transportation functions of the Castle Shannon Railway tunnel, which was originally a coal mine, but later used as a tunnel to transport coal,[2] and later passengers, under Mt. Washington. Although this tunnel was closed to passengers in 1880,[3] the urban legend persists that the Mt. Washington Transit Tunnel was originally a coal mine.

The tunnel was upgraded to allow for joint use by bus and trolley traffic in 1973, with several changes since.


Northern exit of tunnel in 1968 showing site of both accidents

Two spectacular runaway accidents are associated with the tunnel, which is on a steep gradient averaging over 6 percent, and curves as the north portal is reached.

On December 24, 1917, Knoxville service car 4236 ran away downhill after becoming detached from the wire and derailed and overturned on the curve into Carson Street.[4] The car slid on its side until hitting a telegraph pole which ripped the roof off. Twenty-one people were killed and 80 were injured; the claims from the accident sent Pittsburgh Railways into receivership.[5]

On October 29, 1987, a 1700-series all-electric PCC car began to exceed the tunnel's speed limit as it entered the south portal after departing South Hills Junction. The operator, realizing the car could neither stop nor take the sharp curve from the transitway to the Panhandle Bridge ramp, ordered all the passengers to move to the back, and radioed the PAT central dispatcher to clear Station Square. The car left the rails and took Smithfield Street instead (the trolleys' original route downtown, until 1985), crossing Carson Street, sideswiping a PAT bus and a truck, and knocking out a fire hydrant. Miraculously, the car stayed on its wheels, and finally stopped next to the Pittsburgh History & Landmarks Foundation, the former Pittsburgh and Lake Erie station building at Station Square. Thirty-seven people were injured, four seriously, but there were no fatalities. All three braking systems on the car had failed: the drum, dynamic, and magnetic rail brakes.[6] Most of the 1700 series cars were found to have electrical defects, prompting PAT to retire all of their remaining PCC's that had not been rebuilt as 4000 series cars. Consequently, PAT was left with a shortage of cars, which contributed to the closure of the Overbrook line in 1993.[7]


  1. 1.0 1.1 Middleton, William D. (1967). The Time of the Trolley, p. 195. Milwaukee, WI (US): Kalmbach Publishing Co. LCCN 67-20155.
  2. Chance, Henry Martyn (1884). Report of Progress... pp. 179–180. Retrieved 2008-09-08.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  3. Cridlebaugh, Bruce S. "Mt. Washington Transit Tunnel". Retrieved 2008-11-02.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  4. "14 Persons Killed Wild Dash of Runaway Car". The Toronto World. December 25, 1917. Retrieved April 29, 2011.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  5. Smith, Harold A. (1992). Touring Pittsburgh by Trolley. NY: Quadrant Press. pp. 4–5. ISBN 0-915276-48-8.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  6. Associated Press (October 29, 1987). "Runaway Pittsburgh trolley injures 37". Los Angeles Times. Retrieved 29 April 2011.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>
  7. Dupuis, Roger II. "Pittsburgh Railways history (Page 6)". Pittsburgh Railways OnLine. Retrieved 29 April 2011.<templatestyles src="Module:Citation/CS1/styles.css"></templatestyles>

External links

  • Lua error in Module:Coordinates at line 668: callParserFunction: function "#coordinates" was not found. - Southern portal
  • Lua error in Module:Coordinates at line 668: callParserFunction: function "#coordinates" was not found. - Northern portal