As such, the tracks connecting to the IND Sixth Avenue Line comprise the IND 63rd Street Line, on the south side of the station, while the tracks connecting to the BMT Broadway Line comprise the BMT 63rd Street Line, on the north side of the station.
Therefore, the tracks linking to the IND Sixth Avenue Line are comprised of the IND 63rd Street Line on the southern side of the station, while the tracks connecting to the BMT Broadway Line are made up of the BMT 63rd Street Line on the northern side of the station.