System for automatically delaying application of a snow brake for a railway vehicle

A "snow brake" control system for a railway vehicle having brake apparatus to apply and release the vehicle brakes, said brake apparatus including a slack adjuster that is operative in response to movement of said brake apparatus from a brake application position to a brake release position, said "snow brake" control system comprising:

• (a) means for providing a first brake control pressure in accordance with the degree of brake desired during a normal brake application;
• (b) means for providing a second brake control pressure at a predetermined level to provide a "snow brake" application during release of said normal brake application;
• (c) relay valve means subject to said first and second brake control pressures for effecting operation of said brake apparatus;
• (d) valve means for connecting one or the other of said first and second brake control pressures to said relay valve means;
• (e) electro-pneumatic valve means for establishing or interrupting the communication of said second brake control pressure with said valve means;
• and
• (f) timing means operative in response to the release of said first brake control pressure for controlling said electro-pneumatic valve so as to interrupt said communication of said second brake control pressure with said valve means for a predetermined time period and thereby delay said "snow brake" application for a period of time sufficient to allow said brake apparatus to move from said brake application position to said brake release position.