The Eighth Avenue Line is a public transit line in Manhattan, New York City, United States, running mostly along Eighth Avenue from Lower Manhattan to Harlem. Originally a streetcar line, it is now the M10 bus route and the M20 bus route, operated by the New York City Transit Authority. The M10 bus now only runs north of 57th Street (near Columbus Circle), and the M20 runs south of 65 street. The whole line was a single route, the M10, until 1999 when the M20 was created.
Eighth Avenue Line (Manhattan surface) Wikipedia
The Eighth Avenue Railroad opened the line from the north end of the trackage shared with the Sixth Avenue Railroad's Sixth Avenue Line at Canal Street and Varick Street along Canal Street, Hudson Street, and Eighth Avenue to 51st Street on August 30, 1852. It was eventually extended north to 159th Street, with a branch along Macomb's Lane to 154th Street, and another branch to the south along Canal Street east to Broadway. Buses were substituted for streetcars by the Eighth Avenue Coach Corporation in March 1936, a company owned by Fifth Avenue Coach Company. The New York City Omnibus Corporation took over operations in 1951, and in 1956 it was renamed Fifth Avenue Coach Lines; the Manhattan and Bronx Surface Transit Operating Authority replaced it in 1962.
In 1962, when the Surface Company bought 8 Avenue they put one bus service for the entire length. This was given the route number 10, which then became bus M10. In 1999, the M10 was split into two routes: The northern section from Harlem to Penn Station was the M10. The southern segment from Columbus Circle to Battery Park CIty became the M20. Due to a budget crisis, M10 buses were truncated at its south end to 59th Street-Columbus Circle starting on June 27, 2010. Also, on that same date, the M20 was extended to South Ferry. In April 2011, however, M10 service was restored to 57 Street only. The last stops on these buses now are 58 street and Broadway instead of 59 street and 8 Avenue.