A section of a highway overpass collapsed before dawn Saturday in rural southeastern Missouri near Chaffee, 15 miles southwest of Cape Girardeau, after about a dozen rail cars derailed and struck the support pillar.
The rail cars derailed after a Union Pacific train T-boned a Burlington Northern Santa Fe (BNSF) train, about 120 miles south of St. Louis, Scott County.
AP reports officials say there were only two cars on the overpass at the time of the accident.
CNN, however, reports that Trooper Clark Parrot, spokesman for the Missouri State Highway Patrol, said there were no cars on the overpass at the time it collapsed. The two cars drove into the collapsed structure in the dark.
According to CNN, seven people were injured, five in the two cars and two on a train. The victims, including a Union Pacific train conductor and an engineer, were taken to St. Francis Medical Center in Cape Girardeau. Walter said a deputy who arrived at the scene soon after the crash pulled the two Union Pacific employees out of the wreckage.
Hospital spokeswoman Felecia Blanton, said all the patients were released on Saturday. AP reports she said the injuries were relatively minor.
According to Reuters, County Sheriff Ricker Walter confirmed the victims suffered minor injuries only.
The sheriff said that although the sections of the highway overpass that crumpled were about 15 years old, they were in good condition but simply could not withstand rail cars smashing into their columns.
Sheriff's dispatcher Clay Slipis, said: "One train T-boned the other one and caused it to derail, and the derailed train hit a pillar which caused the overpass to collapse."
According to AP, Walter said: "You're driving down the road and the next thing you know the bridge is not there... It could have been really bad."
Fire broke out after the collision but was put out quickly. The fire was sparked by diesel fuel that leaked out of a train engine.The derailed cars were carrying scrap metal and auto parts from Illinois to Texas.
A witness, Wayne Wood, said he ran to the scene after he heard a c rash. Reuters reports he said: "We heard the crash and we stepped outside and my son said the overpass was down. Then we heard a car's tires squealing like it was coming to a stop and then a crash and a horn continuously blowing. I got over there, the train was on its side. They got the guys out and lifted them down off the train and got them off the overpass. One was kind of bloody and the other one looked like he was pretty shook up [shaken]."
The spate of traffic infrastructure collapses in recent times have raised concerns about aging infrastructure. Last week, 70 people were injured when a commuter train derailed in Connecticut and struck another train, Reuters reports.
Digital Journal reported that the I-5 Skagit River Bridge collapsed partially after a truck hit it. Two cars plunged into the river. Rescuers pulled out three people.
The National Transportation Safety Board says it is investigating the cause of the train collision, AP reports.
Robert Sumwalt, an NTSB board member, said it may take a year to complete investigations, according to Reuters. He said the agency will conduct a thorough review of operating procedures and performance of crews. He said "there is no similarity" between the Missouri accident and the Skagit bridge collapse because the Missouri bridge was rated "good" after a February inspection.
He said: "This was not because of any lack of integrity of the bridge in southeast Missouri, but because of a train that derailed and had a bunch of rail cars slamming around."