Abstract: A strainer device for railroad car air brake combined dirt collector and cut out cocks, and arranged to be applied within the swirl chamber of such cocks, and between the collector bowl, about the pedestal thereof, and the lip of the cock throat chamber, which strainer device comprises an outer shell that is open and flanged at both ends, with one end of the outer shell being disposed adjacent the throat lip, an annular seal applied between the said outer shell one end and the throat lip, an inner shell disposed within the outer shell and secured at the other end of the outer shell and adapted to receive the cock collector chamber pedestal, and a compression spring received about the pedestal within the cock collector bowl and resiliently seated against the outer shell end flange at that end of same for spring biasing the other end of the outer shell and the seal against the throat lip.