TheBroadway Line is asurface transit line inManhattan,New York City, running mainly along42nd Street andBroadway fromTimes Square toHarlem. Formerly astreetcar line operated by theThird Avenue Railway, it is now theM104bus route operated byMaBSTOA, a division ofMTA Regional Bus Operations. This bus route no longer runs along the entire route of the former streetcar.
The M104 route begins at 41st Street and 8th Avenue, by Times Square. Buses use Eighth Avenue (northbound) and Seventh Avenue (southbound) to and from Central Park South. The route continues north on Broadway through theUpper West Side, finally turning off at125th Street, where it turns around at a clockwise loop onAmsterdam Avenue,129th Street, Convent Avenue, and 125th Street.

TheForty-second Street, Manhattanville and St. Nicholas Avenue Railway opened theBoulevard Line in 1884 or 1885, following the42nd Street Crosstown Line from theEast 34th Street Ferry alongFirst Avenue (trackage rights over theCentral Park, North and East River Railroad'sEast Belt Line) and 42nd Street toTimes Square, using new trackage on Broadway (then Boulevard) to125th Street, and turning west on 125th Street over the tracks of theOne-Hundred and Twenty-Fifth Street Railroad's125th Street Crosstown Line to theFort Lee Ferry.[3] TheThird Avenue Railroad acquired control of the line in November 1895,[4] and theMetropolitan Street Railway leased the Third Avenue in May 1900.[5]
Effective February 17, 1908, as part of the splitting of the Third Avenue Railroad from thebankrupt Metropolitan Street Railway, the Third Avenue's Broadway cars were sent along their old route, heading east on 42nd Street atTimes Square and ending at theEast 34th Street Ferry viaFirst Avenue. Simultaneously, the Metropolitan introduced a new line,[6][7] theBroadway and Amsterdam Avenue Line, running from Broadway and Houston Street along Broadway,Seventh Avenue,53rd Street,Ninth Avenue,Columbus Avenue, Broadway, andAmsterdam Avenue to125th Street.[8] This was done because the Third Avenue's Broadway trackage ended at Times Square; south of Times Square was Metropolitan trackage.
In June 2010, due to budget cuts, the M104 bus route was truncated toTimes Square from theHeadquarters of the United Nations, eliminating service along 42nd Street.[9]