摘要 |
A railway vehicle fluid pressure operable emergency vent valve responsive to a reduction of brake pipe pressure at a rate in excess of a certain rate, or at an emergency rate, for unrestrictedly venting the brake pipe to atmosphere and thus propagating an emergency brake application, but also sensitive and operable responsively to a reduction of brake pipe pressure, irrespective of rate or at a normally undetectable rate, to a value insufficient for effective brake control, for initiating an emergency brake application. |