 The NTSB found that Train 214 had come to a stop entirely within the faulty circuit B2 @-@ 304 , making it effectively invisible to the automatic train control system . Other trains had received speed commands of 0 when traveling through this circuit but had enough forward momentum to make it to the next circuit and resume detection and receipt of speed commands from the ATC system . Train 214 was going slower than normal because it was being driven in manual mode by its operator , and it came to a stop while remaining on circuit B2 @-@ 304 and was therefore invisible . Train 112 behind it was given full speed commands by the ATC to proceed on the track . The investigation found that the emergency brakes had been applied by the operator of train 112 when train 214 came into view but it was too late to avert the collision . 
