Double Track - Quadruple Track

Quadruple Track

Quadruple track consists of four parallel tracks. On a quad-track line, faster trains can overtake slower ones. Quadruple track is mostly used when there are local trains that stop often (or slow freight trains), and also faster inter-city or high-speed trains. The most notable example of quadruple track in the United States, and perhaps the only four-track section of mainline therein, was the Pennsylvania Railroad's main corridor through the heart of Pennsylvania around the famous Horseshoe Curve. This line is now owned by Norfolk Southern. Other examples include the Hudson and New Haven Lines, both of which are shared between Metro-North and Amtrak in New York and Connecticut. The New Haven Line is quadruple track along its entire length, while the Hudson Line is only quadruple track along the shared portion from Spuyten Duyvil to Croton-Harmon and along the length from Grand Central to Yankees-E 153 St.