Many metro trains are automated for their route. If the standard cruise speed for the train is 49 mph and the train can accelerate at 7.6 m/s/s, for how many seconds does the train need to accelerate from rest at the station to its cruise speed? Many metro trains are automated for their route. If the standard cruise speed for the train is 49 mph and the train can accelerate at 7.6 m/s/s, for how many seconds does the train need to accelerate from rest at the station to its cruise speed?