An electric door operator for opening and closing one or a spaced pair of transit vehicle passenger doors for being mounted over an opening for the doors. A rotatable input shaft has an electric motor secured to the input shaft for driving the input shaft, a worm centrally positioned on the motor shaft, and an electric brake mounted to the input shaft at an end opposite of the electric motor. A drum cam lifts a pinion from a worm gear disconnecting the worm gear from an output gear train in an emergency.