The driver of a trailer carrying 12 military veterans and their wives in a Midland, Texas, parade continued through a railroad crossing even as the intersection's warning lights and bells alerted traffic to stop, federal investigators said Saturday.
But what National Transportation Safety Board officials have not determined is whether the driver in Thursday's crash noticed the warnings and whether the crossing system's safeguards were working properly, giving the driver sufficient time to act.
In a briefing Saturday, NTSB member Mark Rosekind listed what happened in the moments before the accident, a meticulous breakdown of the events leading to four deaths and 16 injuries:
Twenty-one seconds before the crash, the crossing's southbound traffic signal turned green.
At 20 seconds, the crossing's warning lights began to flash and the bells sounded. At the same time, the lead parade float's trailer crossed the southern edge of the track's rail and made it through.
Thirteen seconds before impact, the crossing arms began to come down.
One second later, the trailer carrying the veterans began crossing the track, its front tires rolling over the northern edge of the rail.
Three seconds later, the train engineer blasted his horn, stretching out the blare for four seconds.
Seven seconds before impact, one of the crossing arms crashed into a flagpole on the parade float.
Two seconds later, the engineer hit the emergency brakes.
At 4:36 p.m., the 80-car train slammed into the trailer at 62 mph. It took more than a minute to come to a complete halt.
"What we're really looking at is layers of protection here," Rosekind said. The lights and bells start so traffic can stop, but the gates come down several seconds later so vehicles can get out of the way, he said.
The 20-second warning time is the federal minimum.
"There's typically going to be at least a 20-second period before the train is going to be in that crossing," Rosekind said. "It doesn't always happen that way."
The Union Pacific locomotive had a pristine maintenance record and had no mechanical anomalies, investigators concluded. The track speed limit in that area is 70 mph, so the train was going slower than required.
Investigators interviewed the train's conductor and engineer Saturday. They have reached out to the driver's company, which they did not identify. NTSB officials have said the driver voluntarily gave police a blood sample.
The accident was a tragic end to what was supposed to be the start of a relaxing weekend for the veterans. Besides the parade, the group was booked for an all-expenses-paid hunting trip. Instead, a community is grieving.
Police identified the dead as Army Sgts. Maj. Gary Stouffer, 37, and Lawrence Boivin, 47, who were pronounced dead at the scene, and Sgt. Joshua Michael, 34, and Sgt. Maj. William Lubbers, 43, who died later at Midland Memorial Hospital. Four people remained hospitalized, including one in critical condition.