In June 1874, New York City Mayor William Frederick Havemeyer refused to sign warrants in payment for the project as he believed that the Legislature's act was unconstitutional. He had signed the warrants until this point, when 2/3 of the work was completed. On May 3, 1875, the first section of the improvement between 56th Street and 94th Street was placed in full revenue service, running through the cut south of the Yorkville Tunnel. On June 20, the entire improvement opened, and the first trains from Grand Central to the Harlem River were witnessed by large crowds of spectators. That morning, new rails and ties were installed between 96th Street and 33rd Streets, and the old track and trestle were demolished. The first train, the St. Louis Express, due at 12:30 p.m., arrived late at 1:50 p.m. due to the work. Masonry work continued to be done to lengthen the tunnel at Yorkville down to 80th Street, arching over the tracks. The tracks were not yet ballasted, forcing trains to run slowly. The side tracks to be used for local rapid transit trains were not yet laid, and the passenger stations at 59th Street, 72nd Street, 86th Street, 110th Street and 125th Street were not yet built. At this time, local rapid transit trains were expected to begin operation by September 1875 and were to serve stations yet under construction. The rolling stock for the local trains were to be much lighter than those used on the through trains.