Brooklyn Rapid Transit Company), all working together to make the construction of the Dual Contracts possible. The Dual Contracts promised the construction of several lines in the Bronx. As part of Contract 3, the IRT agreed to build an elevated line along Jerome Avenue in the Bronx. The first part of the line opened on June 2, 1917 as a shuttle service between Kingsbridge Road and 149th Street. Only the southbound platform was in use at Kingsbridge Road. This was in advance of through service to the IRT Lexington Avenue Line, which began on July 17, 1918. The line was extended from Kingsbridge Road to its final terminal of Woodlawn on April 15, 1918. This section was initially served by shuttle service, with passengers transferring at 167th Street. The Jerome Avenue line cost approximately $7 million, with $3 million spent on the elevated section and $4 million spent on the underground section. The construction of the line encouraged development along Jerome Avenue and led to the growth of the surrounding communities. On July 1, 1918, trains on the Ninth Avenue El were extended from 155th Street, entering the Bronx via the Putnam Bridge, a now-demolished swing bridge immediately north of the Macombs Dam Bridge, to connect with the Jerome Avenue line between 161st Street and 167th Street. Beginning on July 17, 1918, Ninth Avenue El service was extended to Kingsbridge Road. On January 2, 1919, rush hour Ninth Avenue El express trains began running to Woodlawn. On December 11, 1921, Lexington Avenue–Jerome Avenue subway trains began running north of 167th Street at all times, replacing elevated trains, which ran to Woodlawn during rush hours, but terminated at 167th Street during non-rush hours. Four were killed and 45 injured in a collision between two trains on April 29, 1929, two hundred feet north of 167th Street station. Later changes Following the closure of the lower portion of the Ninth Avenue Elevated on June 11, 1940, service from 155th Street to Burnside Avenue in the Bronx was continued as the "Polo Grounds Shuttle," or the 155th Street Shuttle, at all hours. A paper transfer issuance was established between the shuttle and the IND Concourse Line station at 155th Street at the Polo Grounds. IRT composite construction subway cars replaced the wooden elevated cars on the line, but retained the elevated third rail shoes. Dual third rail operation remained in use on the