In 1872, the New York City Rapid Transit Company was chartered, authorizing Vanderbilt to build and operate a two-track extension of the line from Grand Central to City Hall Park, connecting with the existing line between 48th Street and 59th Street. The line would have run from Broadway's east side at City Hall Park east to Chatham or Centre Street, then to Park Street, Mott Street, the Bowery, Third Avenue, and Fourth Avenue to connect with the existing line between 48th Street and 59th Street. While Cornelius Vanderbilt had indicated his intent to continue the underground line to City Hall, there was speculation that he did not intend to build the section south of 42nd Street. The Superintendent Engineer of the project, Isaac Buckhout, said that he had been receiving proposals for the project and that all surveys for it had been completed by January 1873. The estimated cost of the project made by Buckout came out to be $9.1 million. William Henry Vanderbilt stated that the line would not be as dark as the Metropolitan Railway (now part of the London Underground), and that there would be stations every eight blocks, or every . In January 1873, he expected the cost of the work to City Hall to be $8 to $10 million, and that the whole project would be completed by January 1, 1875. The line was expected to have 400,000 daily passengers, and trains would have traversed the line from City Hall to Grand Central in 12 minutes, and from there to the Harlem River in 10 minutes.