In southwestern Pennsylvania, the 4,541-foot-long (1,384-meter) tunnel that runs underneath Laurel Ridge has had many uses since it was first carved out in the late 19th century. Originally the structure had been built for a planned South Pennsylvania Railroad, but after that project fell through, the structure was incorporated into a new high-speed roadway, the Pennsylvania Turnpike. When it first opened in 1940, the turnpike was hailed as the newest, fastest way to travel across the state. But the single-tube Laurel Hill Tunnel, along with several other tunnels along the…
