On October 24, 1920, service was extended again to Westchester Square. On December 20, 1920, service was extended to Pelham Bay Park. Service to Pelham Bay Park was served by a mix of through and shuttle trains during the 1920s. On December 21, 1925, the number of Manhattan-bound through trains in the morning rush hour, between 7 a.m. and 8 a.m., was increased from thirteen to eighteen, a 38 percent increase in service. The remainder of trains continued operating as a shuttle service to Hunts Point Avenue. On January 28, 1931, two southbound morning rush hour trips began starting at Pelham Bay Park instead of Hunts Point Avenue. On April 13, 1931, service to Pelham Bay Park was increased. Two additional southbound trips were added, starting at Pelham Bay Park at 5:50 and 6:10 a.m., reducing headways from ten to five minutes. Four northbound trips that terminated at Hunts Point Avenue between 3:53 and 5:05 p.m. were extended to Pelham Bay Park, reducing headways from nine to six minutes, and four northbound trips terminating at Third Avenue—138th Street between 3:36 and 4:48 p.m. were extended to Hunts Point Avenue, reducing headways from to 3 minutes. By 1934, service south of the City Hall station had been discontinued, and late night service ran from Pelham Bay Park to 125th Street only, being replaced by local service on the 4, which had previously run express. Under the New York City Board of Transportation Effective December 31, 1945, City Hall station closed with the former Brooklyn Bridge station (renamed to Brooklyn Bridge–City Hall) being the permanent southern terminal. However, the 6 train still uses the loop to get from the southbound to the northbound local track at Brooklyn Bridge–City Hall. On May 10, 1946, late-night service was extended from 125th Street to its previous terminus at Brooklyn Bridge when late night express service on the 4 was restored. Beginning October 14, 1946, weekday rush and Saturday morning rush peak direction express service started, with Pelham Bay trains using the middle track between East 177th Street and Third Avenue–138th Street. This express service saved eight minutes between Third Avenue and East 177th Street. During this time, 6 trains that ran local in the Bronx when express trains operated began to terminate at East 177 Street to make room for express trains to Pelham Bay Park. On March 7, 1949, the hours of the evening