The front end of a Mack track was captured on surveillance video crossing a Baltimore County railway just three seconds before it was struck by a CSX freight train, said a spokesperson for the National Transportation Safety Board (NTSB) during a press conference Wednesday afternoon.
While investigators still are working to determine what caused Tuesday's train derailment -- which led to an explosion felt by those half a mile away -- NTSB board member Robert Sumwalt said that crash investigators have had an "extremely productive day."
Investigators spent Wednesday culling evidence from surveillance video, both from a warehouse near the scene of the crash and from a track image recorder mounted on the front of the locomotive. They also are examining data from locomotive event recorder and physical evidence.
The CSX freight train, which consisted of two locomotives and 45 cars, apparently collided with a trash truck in the Rosedale section of Baltimore County around 2 p.m. Tuesday.
Less than six minutes later, an explosion blasted the fronts of nearby warehouses and sent black smoke streaming into the sky about a mile east of Interstate 95.
Investigators were not able to get until the crash site until Wednesday morning due to the amount of time firefighters had needed to battle the resulting blaze.
Of the train's 45 cars, 14 were loaded and four contained hazardous materials. A total of 15 cars derailed, including three with hazardous materials.
Based on physical evidence at the scene, only the car carrying sodium chlorate exploded, Sumwalt said. Sodium chlorate is an oxidizer used in many industrial processes.
Crews battling the fire Tuesday had to be careful as the chemicals could have mixed with water and soil. Firefighters remained on the scene through Tuesday night, deeming the fire under control about 10 hours after it began.
"We had to let things burn so we could make a determination," said a spokesperson for Baltimore County Police on Tuesday.
The investigation team, led by Pete Kotowski, has constructed an initial timeline of the moments before and after the impact:
-- 17 seconds before impact: The first of three train horn blasts begins. The third blast continues up to the point of the collision. Trains are required to sound their horns as they approach grade crossings.
-- 5 seconds before impact: The front of a 2003 Mack Granite truck comes into view on surveillance video.
-- 3 seconds before impact: The front of the truck begins to cross the track.
-- At impact: The train strikes the right rear tandem axle of the truck.
-- 33 seconds after impact: Warehouse video shows smoke coming from the wreck.
-- 43 seconds after impact: The first flames are visible.
-- 5 minutes 23 seconds after impact: A car containing sodium chlorate explodes.
The driver of the Mack truck, John J. Alban, Jr., was taken to the University of Maryland Shock Trauma Center in Baltimore.
Alban, 50, is a retired Baltimore County firefighter and volunteer firefighter with the Hyde Park Volunteer Fire Company. There's no word on his current condition.
He was driving a 2003 Mack Granite in a roll-off configuration, which allows a trash container to be rolled on and off the truck.
Officials say there was no crossing arm separating the train tracks from the roadway. The train was traveling at 49 mph at the time of the collision, according to preliminary information from the train's data recorder. Crews threw the emergency brake and the train stopped about 9/10 of a mile after the impact.
The owner of the truck is listed as the interstate carrier Alban Waste, LLC, said Sumwalt. The container was being transported from Alban's facility near the scene of the crash to one in Baltimore, about six and a half miles away.
Sumwalt said investigators are hoping to learn more from surveillance videos to determine what Alban was doing prior to the collision.
"I will say that as a ... matter of practice now, for any NTSB investigation, we will obtain cell phone records from the driver of the truck and also from the operators of the train," Sumwalt said.
A CSX locomotive engineer and conductor who were on the train were not seriously hurt.
In the days to come, investigators will measure and diagram the grade crossing, interview the train crew and will collect additional information from the train.
"I want to say that although we've made tremendous progress today, I do want to emphasize we are very early, very early in the investigation," Sumwalt said Wednesday.
Investigators are asking anyone who may have video of the crash to contact them.
"Lots of video these days, everyone has phones and things like that, so there's a lot of video out there, and video can be very helpful..." Sumwalt said. "The surveillance video, that's tremendously helpful. If somebody has some cell phone video, or otherwise video sources that they feel would be beneficial to the NTSB's investigation, we would love to hear from you."
Anyone with video can contact the NTSB by emailing witness@ntsb.gov.