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).
Read more about this topic: Quadruple Track
Famous quotes containing the word track:
“He who rides and keeps the beaten track studies the fences chiefly.”
—Henry David Thoreau (18171862)