Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
A crime scene investigator looks inside a train car after a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and tipped over in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel help passengers at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel help a passenger at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a deadly train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/ Joseph Kaczmarek)
Emergency personnel help passengers at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel help a passenger at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel work the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
Emergency personnel help a passenger at the scene of a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)
A crime scene investigator looks inside a train car after a train wreck, Tuesday, May 12, 2015, in Philadelphia. An Amtrak train headed to New York City derailed and crashed in Philadelphia. (AP Photo/Joseph Kaczmarek)