[4] Both of the involved trains consisted of Kawasaki M8 railcars, which first entered service in 2011 and were still being delivered at the time of the crash.

[5] This was the first major crash on any of the MTA commuter rail systems in more than a decade, and it is also the first involving the M8 railcars.

St. Vincent Medical Center reported 46 people were treated there, with six being admitted in stable condition.

[11] A limited number of Metro-North and Amtrak trains began to run between New York and New Haven during the afternoon of Tuesday, May 21.

[15] The NTSB sent a portion of the track to a laboratory for analysis of a fracture and foul play was ruled out.

[10] An inspection two days before the crash revealed vertical movement of the track system around an insulated rail joint due to insufficient ballast.

It states that the cause was broken compromise joint bars (used to join two different sizes of rail).

From the inspector's point of view, they would be unable to see all parts of the track due to distance issues.