through the tunnel over to Long Island City and from there continue toward Flushing. At Queensboro Plaza, the line met the BMT's 60th Street Tunnel, as well as a spur from the elevated IRT Second Avenue Line on the Queensboro Bridge. From this point east, the Flushing and Astoria Lines were built by the City of New York as part of the Dual Contracts. They were officially IRT lines on which the BMT held irrevocable and equal trackage rights. Because BMT trains were wider, and the platforms had been built for the IRT, normal BMT trains ran only to Queensboro Plaza, with a transfer to shuttles, using elevated cars, that alternated between the Astoria–Ditmars Boulevard and Flushing–Main Street terminals. IRT trains simply continued from the Queensboro Line and Queensboro Bridge onto the lines to Astoria and Flushing. The line to Flushing was originally called the Corona Line or Woodside and Corona Line before it was completed to Flushing. The line was opened from Queensboro Plaza to Alburtis Avenue on April 21, 1917. The Flushing Line was initially derided by opponents, as it passed through agricultural areas rather than connecting populated places, as previous lines had. Rapid development quickly followed once the Flushing Line was operational, with six-story apartment buildings being erected directly on the former fields, and several major firms building housing for their workers along the route. By June 1917 ridership on the line was exceeding expectations, with 363,726 passengers using the Corona Line that month, 126,100 using the Queensboro Plaza station, and 363,508 using the Queensboro Subway. BMT shuttles began to use the Flushing and Astoria Lines on April 8, 1923. Service to 111th Street was inaugurated on October 13, 1925, with shuttle service running between 111th Street and the previous terminal at Alburtis Avenue (now 103rd Street–Corona Plaza) on the Manhattan-bound track. The line to Main Street had been practically completed at this point, but had to be rebuilt in part due to the sinking of the foundations of the structure in the vicinity of Flushing Creek. Once the structure was deemed to be safe for operation, the line was extended to Willets Point Boulevard on May 7, 1927. This extension was served by shuttle trains until through service was inaugurated on May 14. On that date, the opening of the station was formally celebrated; it coincided with the opening of the Roosevelt Avenue Bridge for cars