Abstract: A continual type quick service valve adapted to be independently mounted on a railway car to provide local, supplemental venting of the car brake pipe pressure, as long as the brake pipe pressure continues to be reduced externally. This quick service venting of the brake pipe pressure is achieved utilizing a single piston actuated exhaust valve that is either cyclically-operated between open and closed states or is held open continuously depending upon the degree of brake application in effect. By selective tuning, the open duration of the exhaust valve can be made to exceed the duration the exhaust valve is closed during each cycle of operation or to remain open for the duration of the external brake pipe pressure reduction to achieve high operating efficiency.

Abstract: An improved freight brake emergency valve device providing improved stability against undesired emergency brake applications without degradation of emergency sensitivity. This is achieved, in one aspect of the invention, by introducing a spring force on the emergency piston as the piston approaches emergency position to thereby retard the piston momentum suffiently to allow a random brake pipe pressure fluctuation to dissipate. In another aspect of the invention, a choke and check valve are arranged to create a dashpot effect to retard piston momentum resulting from a random brake pipe pressure fluctuation.

Abstract: An improved freight brake emergency valve providing improved stability against undesired emergency brake applications without degradation of emergency sensitiveity by increasing the "breathing" range of travel of the emergency piston to allow a momentary random brake pipe pressure fluctuation to dissipate, and by providing a volumetric chamber between the quick action chamber "breather" port connection at the slide valve/seat interface and the "breather" choke in order to obtain a momentary fast reduction of quick action chamber pressure to counteract a brake pipe pressure fluctuation during pressure equalization between the quick action chamber and the added volumetric chamber.

Abstract: A freight brake control valve device having an improved quick service function provided by suppressing premature cut off operation of the quick service limiting valve. In one embodiment of the invention, this is accomplished by connecting the quick service volume pressure to the underside of the quick service limiting valve piston during preliminary quick service to counteract the pressure pulse on the opposite side of the piston that occurs during the transition between the preliminary and secondary stages of quick service. In a second embodiment, pressure is created at the underside of the quick service limiting valve piston by dashpot action of the piston itself.

Abstract: A freight brake control valve device having an improved quick service function achieved by providing an additional volume upstream of the quick service limiting valve with which the brake pipe fluid under pressure is equalized during the second stage of quick service to achieve an intensified secondary quick service reduction of brake pipe pressure. Further, a smooth and continuous local reduction of brake pipe pressure occurs without any time lag at the time of transition from preliminary to secondary stage quick service. In a first embodiment of the invention, an exhaust passage separate from the brake cylinder exhaust passage is provided to assure venting of this additional volume in the event the brake cylinder retainer valve is set up. In a second embodiment, the additional volume is vented via the brake cylinder exhaust passage.

Abstract: A freight brake control valve device having an improved quick service function achieved by utilizing a common quick service volume during secondary quick service as well as preliminary quick service, in order to achieve an intensified secondary quick service reduction of brake pipe pressure. Further, a continuing local reduction of break pipe pressure is obtained without any time lag during transition from preliminary to secondary stage quick service. In a first embodiment of the invention, an exhaust passage separate from the brake cylinder exhaust passage is provided to assure venting of the preliminary quick service volume in the event the brake cylinder retainer valve is set up. In a second embodiment, the additional volume is vented via the brake cylinder exhaust passage.