New York City's B and C trains and portions of the A and D trains have been suspended after a train incident on the A line in Upper Manhattan.
Kopp said one passenger was able to kick a train vehicle door open to get into another auto, but that one was also locked.
'This does not look like a failure on the part of the equipment, ' Lhota said.
Delays were reported throughout the subway system, which has been plagued by problems this year.
At least 37 people were injured following an A train derailment in Harlem Tuesday morning.
Three other trains were in the tunnel at the time of the derailment, he said.
The New York City Emergency Management Department described the incident as a partial derailment, which caused a power outage to A, B, C and D trains between 125th and 145th Streets. "People were falling", said passenger Susan Pak, of Englewood Cliffs, New Jersey.
Danny said passengers pried the train doors open to get to another vehicle, which was pitch black and also had smoke. But when he said that there was smoke on the tracks, that's when we became more concerned.
Joe Lhota, the chairman of New York's Metropolitan Transportation Authority, said officials were investigating why the train's emergency brakes went on before a minor Harlem derailment that frightened passengers and resulted in systemwide delays. It said there was smoke, but no fire.
"We're seeing the effects of an outdated transit system", State Sen. "People were falling", said passenger Susan Pak, of Englewood Cliffs, New Jersey. He said the station wasn't smoky, but there was a strong, acrid smell.
It also comes less than two weeks before the start of Amtrak's summer-long work to fix aging infrastructure at New York Penn Station, a project that is expected to increase subway volume as commuters seek alternatives.
Photos posted to social media show passengers walking along the tracks in a dark subway tunnel, using their phone flashlights as a guide.
A report released earlier this month found that rush-hour cancellations and delays on the railroad are at the highest level in ten years.