Updated Monday, May 5, 5:20 p.m.
A preliminary investigation has found that the broken rail that was discovered where the train derailed was manufactured last November and installed this March, the MTA said.
“The MTA has not determined how or why the rail broke. Speed or human error do not appear to be a factor [in the derailment],” MTA spokesman Kevin Ortiz said.
The broken rail section will be sent for testing as the investigation into the derailment’s cause continues.
In a release Saturday, the transit agency emphasized its safety record, and track and other maintenance efforts, and said the city’s subway system has experienced only 17 mainline derailments in the last decade.
Crews spent the weekend removing the subway train that derailed about 10:25 a.m. Friday just south of the 65th and Broadway R and M local stop. By 5 a.m. Monday E, F, M and R service, which had been affected by the accident, had returned to normal along the Queens Boulevard line.
The Brooklyn-bound F train was on the express track when the six center cars of the eight-car train derailed, injuring 19 and forcing about a 1,000 riders to evacuate, officials said. Of those hurt, 15 suffered minor injuries and four were taken to the hospital with potentially serious injuries.