 The cars were ordered so that the new Eighth Avenue Line subway could be operated.In 1949, when all of the R10 cars were delivered and placed in service on the A line, approximately 224 of these R1 cars were transferred to the 36th Street Yard of the BMT Southern Division to relieve a car shortage on the BMT Lines.They were used for service on the BMT 2 (now R) Broadway 4th Avenue Local service, which in 1949 was also extended from Queensboro Plaza to Astoria-Ditmars Blvd., requiring more cars until 1961 when new R27/30 cars were delivered to the New York City Transit System's BMT Lines.