A fire fighting vehicle includes a chassis, a front axle, a rear axle, a powertrain, an accessory drive, and a controller. The powertrain includes an engine, a battery system, and an electromechanical transmission coupled to the battery system, the engine, and at least one of the front axle or the rear axle. The accessory drive is positioned to receive a mechanical input from the engine and the electromechanical transmission. The controller is configured to selectively operate the powertrain in a plurality of operational modes including a standby mode and a hybrid mode. According to the standby mode, the controller is configured to operate the electromechanical transmission using stored energy stored in the battery system to drive the accessory drive with the engine off. According to the hybrid mode, the controller is configured to operate both the engine and the electromechanical transmission.