Federal investigators say the track is considered the “prime suspect” in Saturday’s train derailment in southwest Iowa that killed one person and injured more than 90. John Goglia is a board member of the National Transportation Safety Board. He says there is evidence of a break in one of the tracks at the site in Adams County near Nodaway. He says they don’t know when the track broke. Goglia says there is also evidence pointing to a possible problem with a pair of locomotive wheels. He says the lead set of wheels on the rear truck of the lead locomotive showed signs of coming off the track. He says the lead locomotive could’ve derailed first.The final report from the N-T-S-B may not be complete for a full year. Goglia says the derailment appears to be the result of at least one mechanical failure, not the mistakes of people, although he says you can never rule anything out.Goglia corrected earlier reports about the passenger list, saying there were 241 passengers on the train with a crew of 16. Among the injured, six are still in hospitals, one of them is serious condition.