The project's cost was split between the New York Central, run by Commodore Vanderbilt, and New York City, whose payment of $3.2 million was to be made up from increased taxes from future development. The project was divided into three sections: 45th Street to 49th Street, 49th Street to 79th Street, and 79th Street to the Harlem River. The line was sunk into a tunnel between 59th Street and 96th Street through Mount Pleasant, known as the Yorkville Tunnel. The -long section in the Harlem flats between 98th Street and midway between 115th and 116th Streets was built as a stone viaduct, and reached its highest point at 114th Street. The stone viaduct surrounded earth embankment.