By the first decade of the 20th century, the city sold the Harlem Ship Canal Bridge to the Interborough Rapid Transit Company (IRT), which was constructing the New York City Subway's first line. A branch of the line was to cross the Harlem Ship Canal above Broadway, which involved modifying or replacing the existing bridge. Ultimately, the IRT determined the existing structure could not support the elevated subway line, choosing instead to build the double-decker Broadway Bridge. The need to replace the bridge was further emphasized when, in 1903, the New York State Legislature passed legislation allowing the realignment of the New York Central Railroad's Spuyten Duyvil Line (now the Metro-North Railroad's Hudson Line) along the Harlem River's eastern bank. The railroad wished to avoid a grade crossing with the Metropolitan Street Railway's streetcar tracks on the replacement Broadway Bridge.