Engineer involved in fatal crash that injured more than 100 has sleep apnea.

The "GMA" team of insiders analyze some of the biggest stories trending this morning.

Three sources with knowledge of the briefing confirmed to ABC News that the engineer, Thomas Gallagher, had undiagnosed sleep apnea that was only discovered after the crash.

The train was so crowded the conductor couldn't collect fares.

The train sped up in the seconds before the crash.

The event recorder and video footage have arrived in Washington, D.C.

The NTSB has contacted the engineer, but has not yet conducted an interview.

The engineer told investigators everything seemed to be working.

Investigators will examine at the train's data recorder.

The NTSB is investigating the role PTC might have played.

The woman was hit by debris while standing on the platform.

The engineer of crashed train tested negative for drugs and alcohol.

He's a married father who has worked for NJ Transit for nearly three decades.

Federal authorities are at the scene investigating.

Investigators will compare the crash to an incident that occurred in 2011.

An eyewitness rushed to the aid of a gravely injured woman in yesterday's crash

Many workers from left the station nine hours after the crash.

ABC News took a look at the major train crashes since 2000.

There were 250 passengers on the train that crashed this morning in Hoboken.

What we know about the incident that killed one person and injured dozens more.

Investigators will examine human factors and mechanical issues.

One witness describes the incident as "something I've never seen before."

This is the second crash at the same station in less than six years.

A normally bustling area around Hoboken station was cordoned off.

“We have a train that has gone through the station,” the first call said.

Officials are investigating a commuter train crash into Hoboken Terminal.