Apparatus and method for pneumatically controlled graduated brake pressure release for freight train brake system

Abstract

A release graduating valve for freight brake control is provided for a railcar having a pneumatic control valve, emergency and auxiliary reservoirs each normally charged with pressurized fluid from a brake pipe and a fluid pressure activated brake cylinder device for applying the brakes on the railcar. A selectively operable release graduating valve can include a graduated release valve and a changeover valve which selectively interposes the graduated release valve to exhaust brake cylinder pressure in a graduated manner responsive to brake pipe pressure. Alternatively, the changeover valve can isolate the graduated release valve and direct the pneumatic control valve to exhaust brake cylinder pressure in a conventional manner. The changeover valve can be operated responsive to the pressure in an air pipe supplied with pressurized fluid from a remote source. A permanent release graduating valve can be provided wherein the changeover valve is omitted, in which case the brake cylinder exhaust is always controlled by the graduated release valve. Either configuration of the release graduating valve could be also be utilized in an ECP freight brake control system.

Description

[0001] This application is a divisional application of the invention patent application with the application number 01124842.4, entitled "Pneumatic Control Device and Method for Gradual Relief of Braking Pressure of Freight Train Braking System". technical field [0002] The present application generally relates to a freight train braking control system, and in particular to a pneumatic control device and method for gradationally relieving brake cylinder pressure in the freight train braking control system. Background technique [0003] The traditional freight train braking system is controlled by a pneumatic control valve, and the braking efficiency of each car of the train is controlled by the pressure fluid. One or more locomotives and each car are interconnected by a brake pipe that supplies pressurized fluid from the main air tank on the locomotive to the air tank in each car. In a standard pneumatic freight braking system, there is an on-board air storage tank on each ...

AI Technical Summary

Problems solved by technology

However, the pneumatic control valve control system has two disadvantages: It takes a while for the change in pressure to propagate from the locomotive to all cars—perhaps hundreds of cars

[0005] Another downside is that once the brakes are applied, the only way to relieve the braking force is to vent the brake cylinders to atmosphere so that the pressure is completely relieved from the brake cylinders

These requirements significantly increase the cost factor

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