A football-field-sized swath tore loose from the face of Mount Washington early Tuesday morning, sending a torrent of mud and trees across railroad tracks along West Carson Street and briefly closing the Duquesne Incline.
Pittsburgh officials also ordered a precautionary closure of LeMont restaurant above the slide zone, but an engineer said a visual inspection found no signs of instability around that structure.
No one was injured, and the main impact of the slide was disruption of freight traffic along the Norfolk Southern Railway line. City and railroad crews worked to clear the tracks, a section of which shifted as the hillside tumbled across it.
Officials discuss landslide, stabilization efforts
At a news conference today, officials discussed the causes of the Mount Washington landslide and the efforts underway to clear and stabilize the area. (Video by Bob Donaldson; 4/8/2014)
At a briefing several hours after the slide, Michael Huss, city public safety director, said the ground was still moving in the area.
It was left to engineers and safety officers for the railroad to decide when to resume service, Mr. Huss said. Westbound trains were moving slowly through the area by early afternoon.
As for LeMont, it was to remain closed until engineers from the city and those hired by the restaurant determined it was safe. "We're erring on the side of caution," he said.
The city Bureau of Building Inspection will meet this morning with CEC Inc. -- civil engineers for LeMont -- to determine if the restaurant can reopen Thursday, said Sonya Toler, Public Safety Department spokeswoman.
The slide was reported shortly after 4 a.m. by the engineer of a passing train. The slide area was about 100 yards long and it left a debris field about 10 feet deep and 30 feet back toward the hillside, city Operations Director Guy Costa said.
The Duquesne Incline was closed for a time but reopened when officials determined it was not threatened by the slide. The structure is equipped with sensors that are designed to detect earth movement, Mr. Huss said.
Conductor Lucille Gabler said one of her co-workers on the night shift heard a "funny noise" before closing, but the incline was running normally until shortly before 7 a.m., when someone from the mayor's office told her they'd have to close. The incline reopened around 9:15 a.m.
The Pittsburgh Water and Sewer Authority checked water and sewer lines along Grandview Avenue above the slide and found no damage, Mr. Costa said.
The slide was typical in that it involved a failure of weak claystone called "red beds" that were saturated with moisture from recent rainfall, said Bruce Roth, a geotechnical engineer with GAI Consultants Inc., the company brought in by the city to inspect the scene. "That is a common occurrence in Western Pennsylvania," he said.
In addition to visual inspection, the company will examine the history of the scene and drill to collect soil samples that will be analyzed in a lab, a process that could take about a month. It will then offer the city a variety of options for correcting the problem.
"If they run across something that needs to be immediately addressed, we'll have to address it," Mr. Costa said. "It could be fine. All the loose stone and shale came down, and we don't have to do anything."
Debris from the slide was on railroad property. Allegheny County property records show that the city owns the hillside between LeMont and the railroad line.
Jon Schmitz: firstname.lastname@example.org, 412-263-1868 or Twitter: @pgtraffic. Molly Born: email@example.com or 412-263-1944. First Published April 8, 2014 7:15 AM