| 摘要 |
A microporccessor based electro-pnuematic brake control system for a railway train including both an automatic brake control system and an independent brake control system, in which the independent brake control system includes an application electro-pneumatic valve to control application of air pressure to locomotive brake cylinders in response to an application control signal, and a release electro-pneumatic valve to control release of air pressure from the locomotive brake cylinders in response to a release brake control signal. The application electro-pneumatic valve is biased to a normally closed position, in the absence of a application brake control signal thereto, to prevent venting of application air pressure from the locomotive brake cylinders in the event of a power failure, while the release electro-pneumatic valve is biased to a normally open position, in the absence of a release brake control signal thereto, to prevent trapping of air pressure in the locomotive brake cylinders in the event of a power failure. In addition, the release electro-pneumatic valve is provided with a restricted outlet port to retard exhaust of air from the locomotive brake cylinders in the event if a power failure following a brake application. On brake control systems also having an mu valve to cut-off the independent brake control system in a dead locomotive in a consist, the mu valve is biased to normally be in a closed position to prevent venting of application air pressure via the mu valve in the event of a power failure.
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