Systems and methods for determining compression device degradation of an engine of a rail vehicle are provided. In one embodiment, a rail vehicle system includes an engine, an air-intake passage coupled to the engine, a compression device including a compressor positioned along the air-intake passage, a barometric air pressure sensor for measuring a barometric air pressure upstream of the compressor, a manifold air pressure sensor for measuring a manifold air pressure downstream of the compressor, and a controller configured to adjust a rail vehicle operating parameter responsive to a determination of compression device degradation based on a negative pressure differential between the manifold air pressure and the barometric air pressure during a designated operating condition.