UPPER WEST SIDE, Manhattan (WABC) -- Human error is being eyed in the subway train collision and derailment that injured dozens on Thursday and snarled commuters, according to investigators.
NTSB officials offered an accounting of events Friday afternoon, saying an unruly passenger began activating emergency brakes onboard a No. 1 train, causing it to go into emergency mode, stopping the train.
They say the control center then directed the crew to drop the passengers off and cut the brakes in the first five cars.
The NTSB is investigating how the MTA was moving that disabled train, half of which had no brakes, north to a Bronx rail yard. While that was happening, another northbound No. 1 train collided with the disabled train as the in-service train switched from the express to the local tracks. That train collided with the stalled train and was pushed to the side, partially derailing.
MTA officials appeared to rule out a mechanical failure or a signal malfunction, suggesting human error was the likely cause.
"The passenger train, we believe, had a green light - a signal to proceed - and it was going from the express track to the local track, the train that was out of service didn't have the signal. As a result, it bumped into the train," NYC Transit President Richard Davey said.
The Transit workers Union was quick to point upstairs.
"From my speaking to the vice president and the people who responded to the scene, it was management that was controlling the train," TWU Local President Richard Davis said.
The NTSB doesn't want to commit on a cause just yet, but cautioned to not prematurely cast blame on the train crew.
"We'll look at that as part of the investigation, but I would urge people to be cautious about just blaming, especially, you know, blaming the train crew, we don't know. We'll look at what actions were taken," said NTSB Chair Jennifer Homendy.
NTSB officials said that human error is a "symptom of a system that needs to be redesigned," and said that's why they look broadly at all factors.
They questioned why there were no cameras on the inside or outside of the disabled train, along with no data recorder on board. All three of those safety features would have quickly given investigators the answers they need to find the cause of the crash. They also say that those tools would allow for quicker safety improvements after an incident.
The agency requested the Federal Transit Administration make that a required safety standard in 2015, but nothing happened.
The collision, which injured at least 26 people and forced hundreds of train passengers to evacuate, caused significant damage to the trains and tracks, and it could take weeks to figure out an official cause.
Meanwhile, Thursday's derailment continued to cause major delays for the Nos. 1, 2, and 3 train lines for much of Friday.
Many subway riders learned for the first time on Friday about the delays and cancelations, with some of them showing up at the 96th Street station only to discover that it was closed.
The MTA had several workers on hand to give commuters transit advice on how to bypass the mess at 96th Street.
"I'm really disappointed with the MTA because every day we find something, we've got construction, homeless, every day," one commuter said.
Subway rider Ishmael Clarke, who relies on the Nos. 2 and 3 line, was delayed getting to the Brooklyn Nets game Friday night
"It definitely disappoints because I don't think I have a lot of other options outside of the train," Clarke said.
But there was some cause for optimism. Limited service to Nos. 1 and 3 train lines was restored to and from the reopened 96th Street at 5 p.m., although service is still suspended south of the 96th Street station to 42nd Street.
Limited southbound No. 2 train service has also been restored, with every other train traveling down the west side and the remaining trains traveling south down the east side. Northbound No. 2 trains will continue to run on the 5 line.
It's unclear when service will be restored between 42nd Street and 96th Street as crews work to fix and remove the remaining disabled car.
The NTSB is asking anyone with video or imagery from Thursday's collision to email the footage to them at email@example.com.