Malfunctioning railroad crossing arms at six intersections in Hermitage and Donelson caused major traffic tie-ups across the area Thursday morning.
The problems began before 7 a.m. and continued through the morning commute.
At some locations, the arms stayed down even after the Music City Star commuter train had passed and at others, the arms didn't lower until the train was already in the intersection.
Metro police directed traffic at several of the locations, including Andrew Jackson Parkway at Old Lebanon Dirt Road and Old Hickory Boulevard at Central Pike.
The general manager of the Nashville and Eastern Railroad Corporation, which owns the railroad and rents them to the Music City Star, told News 2 that in his 27 years of experience he's never had six railroad crossings malfunction simultaneously.
Craig Wade said the mayhem followed a Nashville Electric Service power surge.
Holden Miller, a spokesperson for NES, told News 2 a substation breaker tripped and closed back at 6:32 a.m. but added, "The question of why the crossing arms didn't function properly for an extended amount of time is a question for the railroad."
Railroad officials said in 27 years, they have never had crossing arms at six rail road intersections all malfunction simultaneously.
"We had a power surge in the area that caused gates to stay down at the crossings," Craig Wade with Nashville and Eastern Rail Road said. "It's never happened before in the 27 years we've been here. We were very concerned. We knew it was going to cause grid lock."
Rail road officials say they are still unclear what caused the malfunction, but the system is back up and running.