Unexplained , intermittent failures persist despite repairs , Passenger official says . Passenger recalls loud bang , `` accordion-like '' collapse of floor , screams . Delegate chides NTSB for making high-cost , `` impossible '' recommendations . `` We 're left with a very compelling mystery as to what is going on here , '' he said . Nine people killed , scores injured in last month crash near Fort Totten Red Line 's station .
Unexplained , intermittent failures persist despite repairs , Passenger official says . Passenger recalls loud bang , `` accordion-like '' collapse of floor , screams . Delegate chides NTSB for making high-cost , `` impossible '' recommendations . Nine people killed , scores injured in last month crash near Fort Totten Red Line 's station .