Integrated Railmotive Systems Inc.

Excellence in Engineering

GRADUATED RELEASE ATTACHMENT FOR DIRECT RELEASE VALVES

    Plate A shown below is an air brake diagrammatic drawing of a simple valve designed by Railmotive for the purpose of automatically converting a standard freight car ABDX direct release control valve to a passenger compatible graduated release control valve.


Graduated
Use of the graduated release attachment permits a freight car control valve to react to a gradually increasing brake pipe pressure by gradually decreasing the brake cylinder pressure as is normally done on passenger trains. A simple selector valve also shown on the diagram, turns the attachment on if brake pipe pressure is increased above 100 psi, and maintains it in operation at any lower brakepipe pressure down to 25 psi, which is sufficient to permit all normal brake pipe controls to be imposed on a train without worry about the valve’s resetting to direct release condition.  When such a reset is desired, it can be achieved by venting the brake pipe to zero then recharging to normal freight brake pipe pressure of 90 pso or less, which will not set the valves for graduated release.
    Advantages of graduated release are better control on down grades by permitting full use of locomotive dynamic braking as well as compatibility with passenger equipment in mixed service.
    Railmotive provided 5 prototypes for rack testing as well as all necessary drawings and assignment of patents to WABTEC.