A system and method of measuring torque generated by a drive train like that used in a rotating equipment drive. A drive motor is mounted to a rotatable brake assembly which, in turn, is coupled to a gear drive which, in turn, transmits rotational power. The brake assembly is coupled to a fixed cover of the gear drive by a gearbox torque sensor that prevents rotation between the brake assembly and the housing. The sensor can be a load cell or its equivalent. A control module may be configured to adjust operation of the rotating equipment drive in response to the torque signal. All input torque from the drive motor to the gearbox is measured when the brake is disengaged through the load cell. All input torque at the gearbox output shaft, through back-driving, is measured when the brake is engaged through the load cell.