Cork Run Tunnel

The Cork Run Tunnel, also known as the Berry Street Tunnel, is one of nine tunnels built in Pittsburgh, Pennsylvania on the original Pittsburgh and Steubenville Railroad. The tunnel was built beginning in 1851 as a single-track bore 2,100 feet (640 m) long, approached by deep open cuts, to connect central Pittsburgh with points to the west, on the south side of the Ohio River. A shaft was sunk from the overlying ridge to a point near the midpoint of the tunnel to speed construction and to provide ventilation. Work was suspended in 1856 due to financial troubles, and resumed in 1862. The tunnel was completed in 1865. Immediately upon completion it was apparent that the tunnel needed two lines. The originally 12-foot-wide (3.7 m) tunnel was widened to 25 feet (7.6 m) starting in 1870 for two tracks, and was completed in 1873. Nevertheless, the tunnel continued to represent a bottleneck, since large cars could not pass each other without causing derailments, which happened frequently. By 1889 work began on the Ohio Connecting Railway to relieve the tunnel. At the same time, the Cork's Run valley was filled in to build the Sheraden Yards, feeding the Cork Run Tunnel. By 1906 the tunnel lining had deteriorated, becoming unstable and requiring almost continuous repair. Since the tunnel was so narrow, workers had to take shelter as trains passed. At least one fatal work accident happ

Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).