NEW : NTSB investigators are focusing on a fractured rail . NEW : ` ` It is substantial interest to us , '' an NTSB official says . Bridgeport Mayor Bill Finch said Friday that travel headaches could persist for weeks because the two tracks affected by the derailment -- which are both `` shot right now '' -- may take weeks to repair . ' New York Times reporter Michael Barbaro reports that the investigation has been delayed because of concerns about safety and cost. " Hospitals say they have treated 70 people .
NEW : NTSB investigators are focusing on a fractured rail . NEW : ` ` It is substantial interest to us , '' an NTSB official says . 'New York Times reporter Michael Barbaro reports that the investigation has been delayed because of concerns about safety and cost. " Hospitals say they have treated 70 people .