The IND started advertising bids for the section of the Sixth Avenue Line between 43rd and 53rd Streets in April 1931. However, that May, construction was postponed because of fears that it would disrupt the Catskill Aqueduct, one of the New York City water supply system's crucial water mains to Brooklyn and Queens. The NYCBOT wanted to start work on the section between 33rd and 39th Streets first so that the engineering issues with the H&M tubes and water main could be resolved. In January 1932, the city announced an agreement with the New York City Water Supply Board. The IND wanted to start construction on the Sixth Avenue line by June so that some of the projected train traffic on the Eighth Avenue line, which was slated to open that year, could be rerouted through Sixth Avenue instead. In 1933, the New York City Board of Estimate requested a $25.5 million federal loan for the construction of the Sixth Avenue line.