They won't need a court order for his cell records, ntsb probably had them within hours of the crash. Not sure what the max speed for that subdivision is but for most of the country except for certain places on the east coast, with certain trains max speed for passenger trains is 90mph. At 3-5 over the max speed the engines over speed sensor would have set the bakes unless manually cut out. If the engineer put the train in emergency I would guess it was a mistake not a deliberate act. If the conductor did it from back in the train it would make me wonder. That is something the event recorder data will tell them.
