Hierarchy of Cab Signal Systems
With a traditional signalling system, the engine driver must observe wayside signals and act accordingly, depending on the aspects displayed. This method of operation is susceptible to human failure; if the driver does not respond to a signal aspect, a dangerous situation may result. It is also considered "passive," in that the system does not actively prevent the unsafe conditions from arising. Modern cab signalling is an active system, in that the train will default to a safe condition (i.e., brakes applied) if left unattended as it approaches an adverse signal aspect. Thus, the reliance on humans to ensure absolute safety is somewhat reduced.
Read more about this topic: Cab Signalling
Famous quotes containing the words hierarchy of, hierarchy, cab, signal and/or systems:
“In the world of the celebrity, the hierarchy of publicity has replaced the hierarchy of descent and even of great wealth.”
—C. Wright Mills (1916–1962)
“In a hierarchy every employee tends to rise to his level of incompetence.”
—Laurence J. Peter (1919–1990)
“Pockets: What color is a giraffe?
Dallas: Well, mostly yellow.
Pockets: And what’s the color of a New York taxi cab?
Dallas: Mostly yellow.
Pockets: I drove a cab in Brooklyn. I just pretend it’s rush hour in Flatbush and in I go.”
—Leigh Brackett (1915–1978)
“Change begets change. Nothing propagates so fast. If a man habituated to a narrow circle of cares and pleasures, out of which he seldom travels, step beyond it, though for never so brief a space, his departure from the monotonous scene on which he has been an actor of importance would seem to be the signal for instant confusion.... The mine which Time has slowly dug beneath familiar objects is sprung in an instant; and what was rock before, becomes but sand and dust.”
—Charles Dickens (1812–1870)
“The skylines lit up at dead of night, the air- conditioning systems cooling empty hotels in the desert and artificial light in the middle of the day all have something both demented and admirable about them. The mindless luxury of a rich civilization, and yet of a civilization perhaps as scared to see the lights go out as was the hunter in his primitive night.”
—Jean Baudrillard (b. 1929)