. >> reporter: natiol transportation safety board investigators have started interviewing the crew of the new jersey transit train that crashed into the hoboken station yesterday. the engineer, 48-year-old thomas gallagher, is said to be cooperating, and has provided a blood sample that will be screened for drugs and alcohol. investigators recovered the data recorder from the rear of the train, but are still waiting to access the front cab. n.t.s.b. vice chair bella dinh- zarr: >> once the n.t.s.b. has a successful download, investigators will use that and get that information about the train. >> reporter: investigators will examine the train for signs of mechanical failure, including any brake problems. investigators are also gatherins and reviewing multiple sources of video. lead investigator jim southworth: >> because of the asbestos, because of the unsettled structures that we're not sure about, i'm not allowing anybody to go in there, okay. none of the evidence that's in there is perishable. >> reporter: gallagher is a 29-year transit employee described as an experienced engineer