Complex sentence: The IRT Ninth Avenue Line, often called the Ninth Avenue El, was the first elevated railway in New York City, opened in 1868 as the West Side and Yonkers Patent Railway, a cable-hauled line.
Split into simpler sentences: The IRT Ninth Avenue Line, often called the Ninth Avenue El, was the first elevated railway in New York City. It opened in 1868 as the West Side and Yonkers Patent Railway, a cable-hauled line.