A system and method for automatically maximizing the quantity of a fluid which can be placed within a tank car having a maximum product weight based on the lesser of either an industry maximum product weight limit and a maximum calculated product weight at 2% outage. The system includes a magnetostrictive probe having a movable float and a temperature gauge thereon and mounted within a tank car, such that the float is capable of being buoyed by a fluid. The system further includes a fluid pump capable of activation to transfer fluid from a bulk source to a tank car, and a controller coupled wirelessly to the magnetostrictive probe and an input device, and wired to one of either a fluid pump or shutoff valve, such that the maximum product weight is entered to the controller by the input device and the controller activates the pump or shutoff valve to begin addition of fluid to the tank car.