Updated at 10:08 a.m.
The southbound A train derailment in Manhattan on Tuesday was caused by a piece of rail that was improperly stored on the tracks, officials at the Metropolitan Transportation Authority said late Tuesday.
The cause of the accident appeared to be human error, not a track defect, officials said. The agency is now checking rails across the system to make sure replacement parts are being properly stored.
The accident, which left at least 34 people injured, took place between the 135th Street and 125th Street stations. Two cars jumped the tracks after the emergency brakes were activated, officials said.
Here’s what you might need to know for your morning commute:
• 2, 3, 4 and 5 train service has resumed following earlier disruptions due to a train with mechanical problems at Chambers Street station. Expect delays.
The crash wasn’t the first time a southbound A train has derailed near the 135th Street station.
Nearly 20 years ago — on July 3, 1997 — a southbound A train jumped the track as it passed through 135th Street station at St. Nicholas Avenue. A worker who was fixing the switches at the station had accidentally flipped a switch for the wrong track.
“The 40-ton car broke in two in a jumble of mangled metal, broken glass and sheared-off cables,” The New York Times reported. “One end of…