The episode intensified scrutiny of New York's antiquated subway system - one of the world's busiest, with more than 5.6 million average daily trips - which has drawn the ire of riders as delays soar and incidents build up.
Joe Lhota (LOH'-tuh) says there were no initial indications of equipment or track failure before two cars derailed and scraped a wall on Tuesday morning.
A sudden braking caused a train derailment in Harlem, injuring 30 people and causing massive transit disruption. "All of a sudden it was like the train just started like banging against the walls of the tunnel", one passenger told CBS 2 NY. However, in this case, the extra equipment appeared not to have been properly bolted down.
The accident, which occurred mid-morning on the line, has seen several hundreds of people stranded for over an hour in the tunnels of metro between the stations of 135th and 125th streets, has indicated to the AFP a spokesman for the fire department.
Three other trains were in the tunnel at the time of the derailment, he said. As of 9 a.m., service has been fully restored to the A, B, C, and D lines, though "extensive" delays are-unsurprisingly-to be expected.
The train cars crashed into a wall near the 125th St station in northern Manhattan, newly-minted Metropolitan Transportation Authority (MTA) chief Joseph Lhota said.
An A train derailment triggered power outages across the subway system this morning, causing injuries to 34 passengers and chaos for straphangers stuck underground, according to news reports. "People didn't panic", he said.
The derailed train, which has body damage and caused signal, switch, and track damage, is in the process of being removed from the express track. "It was enough to scare the heck out of us and for me to think I could die in this train", Kopp said.
Photos posted to social media show passengers walking along the tracks in a dark subway tunnel, using their phone flashlights as a guide.
"It was travelling at a normal pace when suddenly, it was like a horse that rears, it has been cast in the top, bottom, all sides", said a traveler to NY 1.
Governor Andrew Cuomo, who oversees the transit system through board appointments, drew heat from New Yorkers for his handling of the MTA and was silent on the derailment throughout the day until he issued a statement hours afterward.
MTA Chairman Joe Lhota said the derailment happened after emergency brakes were applied.