Authorities probing Monday’s deadly Amtrak derailment near Seattle are seeking to determine whether the train’s driver was distracted by a cellphone or another person in his cab at the time of the crash. At a news conference on Tuesday afternoon, Bella Dinh-Zarr, the National Transportation Safety Board official overseeing the probe, said a “conductor who was getting experience and familiarizing himself with the territory” was with the driver when the train rounded a curve at 80 mph—50 mph over the speed limit. Dinh-Zarr said this is common practice in training situations but would nonetheless be investigated. All the train’s crew members are currently hospitalized and have yet to be interviewed following the derailment, which left three people dead and sent more than 75 others to the hospital. While authorities have already determined the train was traveling well over the speed limit, they are now trying to understand why crew members did not activate the train’s emergency brake.