(CBS News) MIDLAND, Texas. - Federal accident investigators are at the scene of a tragic accident in western Texas.
It happened on Thursday evening at a parade honoring war heroes. A train rammed into a float, carrying injured veterans and their spouses.
At least four veterans were killed. Sixteen other people were hurt, some critically.
The annual parade for wounded veterans was on its way to a dinner banquet when it was struck by the train.
"Something I've never seen, something I never heard, and I wish I never hear that again," Joe Cobarobia, who witnessed the accident, said.
Cobarobia was filming at the moment of impact. Investigators are now reviewing his footage.
"One of the veterans was actually under the train," he said. "I didn't know whether to run to him and grab him, because the train was moving fairly quickly."
The flatbed carrying the 26 people was the last float in the parade. The truck was traveling behind another group of veterans and was trailed by a police car. As the truck went across the tracks, witnesses said that the train signal sounded and the guard rails started to come down on top of the flat bed.
Some witnesses say the driver started to cross the tracks before the truck in front had moved away. If true, the driver may have violated federal safety regulations.
The National Transportation Safety Board (NTSB) is interviewing eyewitnesses, including the driver of the semi truck.
"We'll be looking at the driver's qualifications, his training, his medical status and do a 72-hour review of his sleep/work history," Mark Rosenkind, a board member with the NTSB, said at a press conference.
On Friday morning, the tight knit community held a vigil to remember the four who died.
Forty seven-year-old Army Sgt. Major Lawrence Boivin was awarded a Silver Star and a Purple Heart for injuries during a 2004 tour in Iraq.
Gary Stouffer, a 37-year-old Marine, was deployed multiple times to Afghanistan, where he sustained a traumatic brain injury. He was three years shy of retirement.
Sgt. Major William Lubbers, 43, died at the hospital. In 2003, he sustained a gunshot wound when his team was ambushed in Afghanistan.
Sgt. Joshua Michael was the youngest at age 34. He pushed his wife off the truck, saving her life.
"Streets were lined with families. I was there waving flags, and just the incredible change of emotion is devastating," Midland mayor Wes Perry said.
Investigators have a lot to look at, but there's one thing investigators know. On the 70 mile per hour track, the train was going 62 miles per hour, and there was emergency braking. Investigators have yet to determine at what point those brakes were applied.