Vibrations on the Green Line and possible ties to derailments explored in subway
WASHINGTON – Metro’s chief safety officer, Pat Lavin, said Tuesday Metro is investigating a possible connection between Metro rail fasteners and shaking houses located above the Green Line.
Inspectors say some of the fasteners may have been less than a day old when discovered broken.
“I wouldn’t say the rail clips are defective,” Lavin said. “If there’s an issue with a certain clip or a certain batch, those would be explored.”
Residents of D.C. neighborhood Petworth, located above the Green Line, complained to Metro executives last year they believe trains are causing their houses to shake and to vibrate, Metro said.
Metro spokesperson Richard Jordan said contractor Wilson Ihrig and Associates is studying vibrations in homes located near Georgia Avenue-Petworth Station, after the Petworth residents complained.
In addition to the possible vibration problems, engineers say if the fasteners fail, then rails can spread putting trains at risk of derailment.
Metro safety officials told the Board of Directors that the 2015 derailment near Smithsonian Station resulted from defective rail fasteners. Former Metro Deputy General Manager Rob Troup said at the time Metro was supposed to take the track out of service prior to the derailment but human error kept that from happening.
Metro management is not the only group examining the fasteners.
FTA Metro Safety Oversight inspectors said in a December report rail fasteners located near Green Line Station Georgia Avenue-Petworth, appeared brand new but were broken at the clips. FTA conducted the inspection following the complaints from Petworth residents, according to the report.
The clips connect the track to vibration-absorbing slabs below the track, James Nelson and Hugh Saurenman said in a 1983 Wilson Ihrig and Associates report on the egg-shaped fasteners.
“The rail is fastened to the slabs with direct fixation fasteners using standard rail fixation hard ware such as the Pandrol rail clip,” Nelson and Saurenman said.
FTA inspector Winslow Powell said in the December 2016 report the inspectors saw broken though newly installed fasteners, possibly less than one day old, holding the tracks near Georgia Avenue-Petworth Station. Powell said many of the clips that were broken had “fresh breaks – most likely occurring the same day of the inspection, which explains why the clips had not been replaced yet.”
FTA inspectors said in the report that Metro’s use of new 7000 series trains, which are heavier than earlier models, could be causing the premature deterioration.
FTA Metro Safety Oversight has reported problems on other parts of the Metrorail system as well. They said in reports during the last year they saw several defective fasteners in a row, in sections of track on multiple lines. Sometimes so many fasteners were defective that they violated Metro track inspection standards.
FTA inspectors reported incidents of between three and seven defective rail fasteners in a row.
In one instance, Metro single-tracked trains and replaced more than 10 fasteners in a row just outside Smithsonian station October 11 – during the evening rush hour, then-spokesperson Morgan Dye said.
Riders on the Blue, Orange and Silver lines experienced delays between 10 and 30 minutes during and following the singletracking.
Gus Ubaldi, an engineer licensed in Washington D.C. who worked for Washington Metropolitan Area Transit Authority in the 1970s, said Metro’s rail fasteners might be defective, based on the fact that several in a row had to be replaced in some instances.
“They shouldn’t be breaking in great groups like that,” Ubaldi said, regarding Metro replacing several at once.
Ubaldi said a subway system should never have to replace 10 consecutive rail fasteners at once – noting that rail fasteners do not coincidentally fail at the same time.
“These things don’t happen overnight,” Ubaldi said.
Ubaldi referenced the December FTA inspection report of Georgia Avenue-Petworth Station, and said that the fasteners seemed to fail faster than they should.
“Either the forces in there that would normally cause the clip to fail are being imposed at either a heavier weight or greater frequency so that I’m reaching the fail point sooner … or I have a defect in the clip,” Ubaldi said.
While Lavin understands Ubaldi believed the fasteners were defective, he said Metro believes the rail fasteners are working.
Lavin said he also doesn’t believe the 7000 series trains are causing damage to the tracks because the difference in weight is only 250 lbs per wheel or 2000 lbs per car and is distributed between the eight wheels on each car.
Lavin said the failure of several fasteners in a row on a section of track can be connected to whether the track happens to be straight or on a curve.
Those fasteners may need to be replaced more often, he said, but the problem could be “It’s more a function of the geometry of the track.
“If you’re in a curve section of track that has greater stresses, those curves (or sections of track) require greater maintenance because you apply more forces on them,” Lavin said. “So just because of the frequency that you go somewhere (to repair track) is not an indication necessarily of a broader problem.”