Riders on Pittsburgh’s Light Rail T system at Steel Plaza station may have noticed four tracks: one goes inbound, one goes outbound and two veer off to the east. But signs for the two east-bound tracks have been covered or removed and trains don't use them.
The purpose of these tracks was the subject of listener Greg Null’s Good Question! submission. Null said he rides the T from his Dormont home each day and wondered about the abandoned tunnel.
“Where do those tracks go?” he asked.
The track and the tunnel have been in Pittsburgh a long time. It was once part of the Pittsburgh & Steubenville Extension Railroad. The tunnel was originally a part of the Pennsylvania Canal system, which was constructed in the 1830s. It carried passengers from the eastern U.S. to the then-unexplored western states, passing through Pittsburgh.
Engineering Pittsburgh: A History of Roads, Rails, Canals, Bridges and More by the American Society of Civil Engineers described the route of the canal downtown:
The canal ran along the east side of Grant Street. It then curved to the left under what is now the U.S. Steel Building to enter a tunnel under Grant's Hill...The tunnel was built by cut and cover. This was confirmed when engineers for the Allegheny County Port Authority drilled exploratory core holes in the 1980s for design of the Light Rail Transit line to the south of Pittsburgh.
Through its system of interlocking water channels, railways and inclined planes, the Pennsylvania Canal is credited with encouraging expansion west. But between the 1860s and 1900 most of it was replaced by the Pennsylvania Railroad (PRR), which could move across the state faster than the canal network.
Around that time, the Panhandle Bridge was built across the Monongahela River in Pittsburgh. It was updated to keep pace with the volume of freight passing over it; the current span was built in 1903 and raised about a decade later. Several railroad companies used it as an access point to downtown Pittsburgh until Port Authority of Allegheny County (PAT) expressed interest in it in the 1980s. That’s when the agency was planning to replace the old trolley lines that ran across the Smithfield Street Bridge with the modern light rail (known as the T). PAT Program Manager of Service Planning Fred Mergner said the historic span wasn’t structurally sufficient for the larger, newer vehicles.
“One of the big dilemmas was: okay, how do we put an 82-foot car on Smithfield Street between Third Avenue and the Boulevard of the Allies?” Mergner said. “They were little things that weighed in as they went from the long list to the short list.”
Planners then turned their attention instead to the Panhandle Bridge for the new T. PAT purchased the old canal-turned-rail tunnel that was connected to the bridge
By using this path, the T could use the old rail tunnel to go under the Allegheny County Courthouse (then the jail), and then stop at Steel Plaza at Sixth Avenue and Grant Street. From there the T could take one of two paths: continue on to Penn Station using the former railroad tunnel, or go to the new Wood Street Station. At Penn Station, riders could board a local PAT bus, Greyhound or train.
At Steel Plaza, the Port Authority started digging.
“When they built Steel Plaza, I’m pretty sure they just dug the whole ground out,” Mergner said. “You could actually stand on Grant Street and look down and see the box of the station before they covered it over.”
They also dug a tunnel west underneath Sixth Avenue to Wood Street Station, which was in the lower floors of the Max Azen Furs building.
Meanwhile, the existing former railroad tunnel was modified to head south from Penn Station to Steel Plaza, according to former Pittsburgh Post-Gazette and Pittsburgh Press transit writer Joe Grata. But the route proved to be unpopular.
“It was short-lived because no one ever really rode it,” Grata said. “It was never really promoted as a transfer point to downtown, but then again, you didn’t have the opportunity to go to the North Shore at that particular point.”
Around 2007, Port Authority finally shut down the tunnel route from Penn Station to Steel Plaza due to low ridership. Today, that third track is used as a standby location for trains on very busy days, like Steelers games and parades. It was also used this past October when the city hosted the annual Rail-Volution conference. The tracks behind Penn Station are closed to the public, but still visible to people waiting for a ride on the busway.