Signaling and operation on the Washington Metro
system involves train control, station identification, train signaling, signage, and train length. As with any working railroad, communication between train operators, dispatchers, station personnel and passengers is critical. Failures will result in delays, accidents, and even fatalities. It is therefore important that a comprehensive signal system operated by a central authority be in place. This gives individual train and station operators the information they need to safely and efficiently perform their tasks.
Metro uses an automatic train control
(ATC) system, which comprises three sub-systems. Automatic Train Protection
protects trains; it is designed to separate them so that collisions will not occur. Automatic train supervision routes trains and assists in maintaining adherence to schedule. Together, these two sub-systems provide input to the train's cab signals
and to a third sub-system, Automatic Train Operation
, which can control the trains directly. Because of a 2009 collision
caused by an automatic train control malfunction, Metro no longer uses the Automatic Train Operation sub-system.
The Automatic Train Protection system uses coded track circuit technology originally supplied by Rochester-based General Railway Signal
when the line was constructed in the 1970's. This system is vital (safety critical
), and... Read More