THE BRONX - Federal investigators say that the man at the controls during last year's fatal Metro-North derailment in the Bronx had a number of health issues, including an undiagnosed sleep condition. 

According to a medical document made available by the National Transportation Safety Board, engineer William Rockefeller has severe obstructive sleep apnea. 

Additionally, Rockefeller was not found to have any illegal substances in his bloodstream after the crash, but he did test positive for allergy medications that carry a warning against driving and operating heavy machinery. 

Four passengers were killed and 59 injured when the train jumped the tracks near the Spuyten Duyvil station while speeding at more than 80 mph.