The C Eighth Avenue Local[3] is a 19-mile-long (31 km)[4]: 1  rapid transit service in the B Division of the New York City Subway.

Its route emblem, or "bullet", is blue since it is a part of the IND Eighth Avenue Line in Manhattan.

[5] The C operates during daytime hours only between 168th Street in Washington Heights, Manhattan and Euclid Avenue in East New York, Brooklyn, making all stops along the full route; overnight service is replaced by the A train, which makes all stops along the C's route.

Outside of rush hour, local service in Manhattan was usually provided by the AA, later relabeled K, which ran between 168th Street and Chambers Street/World Trade Center.

[13] Beginning August 19, 1933, C service was cut back from Bergen Street, but started operating during non-rush hours.

[19] On August 30, 1976, the CC train replaced the E train as the rush-hour local along the IND Fulton Street Line and IND Rockaway Line, running from Rockaway Park–Beach 116th Street in Queens through Brooklyn and Manhattan to Bedford Park Boulevard in the Bronx, making it the only service to run through all four boroughs served by the subway.

This shuttle ran between Broad Channel and Rockaway Park during off-peak hours, except late nights.

[10][24] In January 1991, a reduction of service along the Central Park West, Eighth Avenue and Fulton Street corridors to remove excess capacity was proposed.

Initially, the C designation would be eliminated, being replaced by the A making local stops in Manhattan and Brooklyn between 168th Street and Euclid Avenue.

[25] On October 23, 1992, rush hour C service was cut back from Rockaway Park–Beach 116th Street to Euclid Avenue.

[26] On May 29, 1994, weekend service between 7 a.m. and 11 p.m. was extended to Washington Heights–168th Street (effectively recreating the old AA) to allow A trains to run express.

The B and the C, which both ran local along Central Park West, switched northern terminals on March 1, 1998, ending the connection between the C and the Bronx.

In March 2021, TWU 100, the union for subway workers, sued the MTA in order to prevent the reduced frequencies from being permanent.

[40][41] In August 2012, the Straphangers Campaign rated the C train the worst of the city's subway services for the fourth straight year.

The group found that the C performed worst in three of the six categories in its annual State of the Subways Report Card: amount of scheduled service, interior cleanliness, and breakdown rate.

It also ranked next-to-worst in car announcement quality, after the 7, but performed above average in regularity of service and crowding.

[43] The New York Times has also stated that the C train "rattled and clanked along the deteriorating maze of tracks beneath the city, tin-clad markers of years of neglect.

[44] The R179s were expected to replace the R32s with some being allocated to the C. However, delivery of the R179s was delayed until 2017 and the R32s momentarily remained in service after the order was completed, so stopgap measures were implemented.

[48][4] In the summers of 2013 and 2014 as well as from May 2015 to February 2019, some 480-foot-long R160As ran on the C, covering half of its fleet, because of the R32s' continuously aging air compressors caused by the entirely underground C route.

[49] On November 6, 2018, some 480-foot-long R179 trains started running on the C,[50] gradually displacing the R160As back to East New York Yard by February 6, 2019.

[51] The R179s periodically experienced major mechanical and technical issues, forcing the MTA to remove them from service.