North American railroad signals generally fall into the category of multi-headed electrically lit units displaying speed-based or weak route signaling. Signals may be of the searchlight, color light, position light, or color position light types, each displaying a variety of aspects which inform the locomotive engineer of track conditions so that he or she may keep their train under control and able to stop short of any obstruction or dangerous condition.
There is no national standard or system for railroad signaling in North America. Individual railroad corporations are free to devise their own signaling systems as long as they uphold some basic regulated safety requirements. Due to the wave of mergers that have occurred since the 1960s it is not uncommon to see a single railroad operating many different types of signaling inherited from predecessor railroads. This variety can range from simple differences of hardware to completely different rules and aspects. While there has been some recent standardization within railroads in terms of hardware and rules, diversity remains the norm.
This article will explain some of the aspects typically found in North American railroad signaling. For a more technical look at how signals actually work, see North American railway signaling.
Read more about North American Railroad Signals: Signaling Aspect Systems, Extant Mechanical and Electrical Signals, Common Signal Rule Classes
Famous quotes containing the words north american, north, american, railroad and/or signals:
“We might hypothetically possess ourselves of every technological resource on the North American continent, but as long as our language is inadequate, our vision remains formless, our thinking and feeling are still running in the old cycles, our process may be “revolutionary” but not transformative.”
—Adrienne Rich (b. 1929)
“If I could put my hand on the north star, would it be as beautiful? The sea is lovely, but when we bathe in it the beauty forsakes all the near water. For the imagination and senses cannot be gratified at the same time.”
—Ralph Waldo Emerson (1803–1882)
“Resolve to win—period—because that is the American system. You take either side—it doesn’t even matter which one—and you go on the attack.”
—Donald Freed, U.S. screenwriter, and Arnold M. Stone. Robert Altman. Richard Nixon (Philip Baker Hall)
“Though the railroad and the telegraph have been established on the shores of Maine, the Indian still looks out from her interior mountains over all these to the sea.”
—Henry David Thoreau (1817–1862)
“The term preschooler signals another change in our expectations of children. While toddler refers to physical development, preschooler refers to a social and intellectual activity: going to school. That shift in emphasis is tremendously important, for it is at this age that we think of children as social creatures who can begin to solve problems.”
—Lawrence Kutner (20th century)