Officials are still trying to determine exactly what caused a Brooklyn-bound F train to derail in Woodside, Queens on Friday morning. Yesterday it was reported that the area where the incident occurred, near the 65th Street station, has been marked as a "critical rail break" area; it was the location of 205 broken rails between 2005 and 2012, the second highest in the city during that span. Now, officials say that the specific rail that broke underneath the train was brand new.

According to AP, that rail had been manufactured in the U.S. in November and installed in March. The MTA says they are now tracking and inspecting other rails from that shipment. "This piece of rail was just installed a few weeks ago, so age of the rail is not a factor," MTA Spokesman Adam Lisberg told ABC. "Why did it happen? That's what we want to know, too."

Altogether, over 1,000 people were rescued from the tunnels after the derailment, which occurred just before 10:30 a.m. Friday. Nineteen people were injured in the incident, four badly enough to be hospitalized. All eight cars from that F train have now been removed from the tracks; E and F train service on the local track is back this morning, and officials hope to restore full normal service on all four affected lines by 5 a.m. Monday.