Last week's subway crash on the Upper West Side of New York City has led to a thorough safety investigation by federal regulators. This probe gained new urgency after an F train derailed in Coney Island on Wednesday. The incidents caused significant disruptions to commutes for thousands of New Yorkers.

Unlike previous collisions and derailments in the subway's long history, the recent incident did not happen in an instant. Instead, it was the culmination of a series of decisions made over nearly an hour. Thanks to internal MTA records obtained by Gothamist, accounts from the National Transportation Safety Board (NTSB), and interviews with transit employees, a detailed timeline of events leading up to the January 4th crash has been reconstructed.

The ordeal began when a 10-car train on the 1 line abruptly stopped near the 79th Street station. The train operator reported to the subway's rail control center that unauthorized individuals had entered an unused conductor cab and activated the emergency brakes. The operator and conductor of the train went onto the tracks to reset the brake valve, but the train remained non-functional. They suspected that a homeless person had pulled the brake and requested additional assistance.

At the scene, an inspector notified dispatchers that multiple emergency brakes had been activated on the train. Transit workers attempted to reset the tripped brake valves, a process that took at least eight minutes. However, the third car from the front of the train proved unable to have its brakes reset.

As a result, transit managers decided to fully deactivate the first five cars of the train. This forced a supervisor to operate the train from the sixth car, relying on an operator in the front car to guide them via radio communication. The train stopped at the 79th Street station to allow passengers to disembark.

The crew continued their journey north, with the plan to park the disabled train beneath 103rd Street on a track not typically used for passenger service. Eventually, it would proceed to the 240th Street subway yard in the Bronx.

However, just north of 96th Street, the supervisor, operating the train blindly, attempted to transfer it to the unused track. Unfortunately, a 1 train carrying approximately 200 passengers was also crossing the same area, transitioning from the express track to the local track. Despite the presence of three signals meant to halt trains without clearance, the two trains collided at a slow speed.

The disabled train was pushed against the tunnel wall, causing its front car to be lifted upwards. The train with passengers was also forced off the tracks. Fortunately, no injuries were reported, but hundreds of riders had to be escorted out of the subway tunnel. The scene quickly filled with emergency responders from the FDNY and MTA crews.

The following day, investigators from the National Transportation Safety Board arrived to begin their inquiry. Chair Jennifer Homendy expressed concerns, noting that their investigation would not be confined to the January 4th derailment. She referenced a subway track worker who tragically lost his life near the 34th Street-Herald Square subway station on November 29th, making this the second accident on New York City Transit's property within 37 days.

The full service on the 1 line is expected to be restored by late Saturday night after extensive repair work.

Adding to the recent transit woes, a train on the F line derailed in Coney Island on Wednesday, narrowly avoiding an accident with the line's elevated structure. Fortunately, no injuries were reported, and authorities continue to investigate the incident.

Responding to concerns about the reliability and frequency of NYC subway service, MTA officials emphasize the unique challenges faced by New York City due to its 24/7 subway system. They note that the need for ongoing maintenance on its tracks hampers the system's efficiency. Additionally, New York's policy of staffing trains with two crew members (an operator and a conductor) sets it apart from cities like London, Paris, and Barcelona, which operate with one crew member per train. This difference in policy significantly impacts the cost of running more frequent subway service in New York City.