The Number 6SL Brake Stand
The automatic brake valve quadrant has six positions:
Quick Charge, Release, Hold, Lap, Service and Emergency.
This is the large handle in the photos below.
Thanks to engineer Robin Becker for the following video demonstrations.
Quick Charge: Located to the extreme left of
the quadrant, is used for a quick charging of the air brake system.
This position is used infrequently.
(2) Release: Located in the first notch to the right of Quick Charge, is used to release and recharge the brakes. This is the normal running position. When moving the lever, the experienced engineer can feel the detents and make the move without taking his eyes off the tracks ahead.
Video of a release (1.4MB mpeg)
(3) Hold: Located in the notch to the right of Release, is used to release the train brakes while maintaining a set on the engine brakes.
(4) Lap: is against the shoulder to the right of Hold, is used to close all ports after a service reduction.
(5) Service: Area where brake pipe pressure can be reduced at a service rate. Length of time in this area determines how much reduction is made. The independent brake also applies at this time.
Video of a 20 lb. reduction (1.8MB mpeg)
(6) Emergency: Located at the extreme right of the quadrant is used for making an emergency brake application.
Video of an emergency application (1.6MB mpeg)
The automatic brake is not affected by the application or release of this brake.
(1)Release: Located to the
extreme left, is used to release an engine brake application. An
application of the automatic brake also causes the independent to be
applied. If the engineer desires to release his engine brakes at this
time while keeping the train brakes applied, he presses down on the
independent lever. This is called "bailing" the independent, and keeps
the engine stretched out from the train.
(2) Apply: Located to the extreme right, is used to make a maximum engine brake application, usually during a stop. Positions between Release and Apply provide a continuously variable amount of application.