Pennsylvania Gov. Tom Wolf has hired Allan Zarembski, a University of Delaware professor and railway track and infrastructure expert, to focus on oil train safety. Up to 70 trains carrying Bakken Shale crude oil travel through the state each week on the way to East Coast refineries. Zarembski will evaluate the state's freight rail system and advise the governor on cost-effective risk reduction and safety, the administration said. Zarembski's contract is for three months.