Metra reviewing cause of glitch that delayed thousands

Metra officials are scrutinizing what went wrong Tuesday after a malfunction in an automatic braking system halted trains at the peak of the afternoon rush.

About 80 trains and thousands of passengers on the Metra Electric Milwaukee District, Rock Island, Southwest Service and Union Pacific lines were delayed.

The glitch started around 5 p.m. and involved the Positive Train Control (PTC) system, technology designed to stop a train if a crash is imminent.

“What happened was a telecom network time-source failure,” Metra spokesperson Meg Thomas-Reile explained Wednesday. “Basically, the times weren’t syncing in the system, and when it did that … some of the devices went back to 2006.

“It was very bizarre. Because of that none of the trains could sync to PTC. And when you can’t sync, you can’t move,” under federal law.

It took about an hour to restore service, as many passengers waited on trains at downtown stations. Some commuters reported a surge in rideshare prices.

“I have been riding for Metra for over 20 years now and I have never seen chaos unfold in Union Station quite like (Tuesday),” DePaul University student Isabella Parra said.

Parra had boarded a Milwaukee District North Line to Grayslake when the problems began. “The train ride home from Lollapalooza seems like a luxury compared to the crowded state of the train car I am currently in,” she said Tuesday.

Metra had experienced PTC system problems with two wayside units earlier Tuesday. Technicians fixed those but “it went further back into the system and it started cascading through everything, so they couldn’t initialize,” Thomas-Reile said.

Now technical staff is reviewing what happened and how to prevent a recurrence.

Not all trains were affected by the mishap and it appears Metra’s busiest route, the BNSF Line, was unscathed.

Typically, the PTC stop system is triggered if an engineer fails to do something such as halt at a red signal. The technology will calculate factors such as the weight of the train, speed and how many feet it will require to stop. Operators are given a warning first.

Congress mandated major freight and passenger railroads to install PTC after a deadly 2008 commuter train crash in California.

But implementing the system took years because it not only involved outfitting train cars and locomotives but also track infrastructure.