Quadruple Track Layouts
As it can be seen from the pictures below in the Gallery of diagrams, the four tracks can be paired either by direction (slow/fast in each pair) or by purpose (speed or direction in each pair).
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Famous quotes containing the word track:
“I was the conductor of the Underground Railroad for eight years, and I can say what most conductors can’t say—I never ran my train off the track and I never lost a passenger.”
—Harriet Tubman (1821–1913)