Abstract: A pressure gauge assembly for use with a railway hopper car is provided. The railway hopper car includes a railcar and a product unloading system that is attached to the railcar. The railcar includes sidewalls, end walls, and at least one bottom wall for defining an interior volume. The product unloading system includes an inlet manifold for channeling pressurized fluid to the interior volume of the railcar, and an outlet manifold for channeling the pressurized fluid to the product unloading system for discharging materials from the railcar. The pressure gauge assembly includes a housing that is attached to the railcar. A first pressure gauge is positioned within the housing. The first pressure gauge is configured to measure a differential pressure between the interior volume of the railcar and the product unloading system.