BRIDGEPORT - First responders who were at the scene of last week's Metro-North collision say it was chaos.

One train was traveling to Grand Central and another was heading to New Haven when they collided after the latter train derailed in Bridgeport. First responders say it was lucky that only 70 people were injured, adding that because it was rush hour, the injuries could have been far more severe.

Emergency response officials say there is much to learn from the harrowing scene. Several stressed the need for regional emergency operations procedures.

The investigation into what caused the crash is ongoing.