LITTLE ROCK, Ark. (AP) — A transportation expert says a deadly head-on train collision in Arkansas proves more needs to be done to improve safety, but worries changes won’t occur before a federal deadline.

Joseph Schwieterman, transportation professor at DePaul University in Chicago, says the government possibly set an unrealistic timetable to have a new safety system in place by Dec. 31, 2015.

The big push for the safeguards, known as positive train control, came after the 2008 crash in which a commuter train collided head-on with a freight train near Los Angeles, killing 25 and injuring more than 100. 

Two Union Pacific crew members were killed and two others injured Sunday when a pair of freight trains collided on the same track near the town of Hoxie in northeast Arkansas.

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