[5] Due to the steep topography of the neighborhoods surrounding the Grand Concourse (under which most of the line runs), several stations were built with entrances both above and below the platforms, including 167th Street and Kingsbridge Road.

[7][8][9][10] As it travels west, a center track forms which leads to the Concourse Yard.

The line then curves south at Mosholu Parkway to the Grand Concourse, from which it derives its name, at 206th Street.

[7] The line curves west before 161st Street–Yankee Stadium and crosses the Harlem River into Manhattan via the Concourse Tunnel.

[12] It was originally planned to end the line just past the Bedford Park Boulevard station, with a provision for an eastern extension.

[11][13] An alternate approach to the current 205th Street station was proposed in February 1929, extending the line across private property onto Perry Avenue.

[8] The building of the line and proposed extensions to central and eastern Bronx (see below) led to real estate booms in the area.

[12] The line was supposed to be completed by January 1933, but this was delayed due to financial difficulties following the Wall Street Crash of 1929.

[17] The CC provided local service between Bedford Park Boulevard and Hudson Terminal (now World Trade Center).

The closure would allow the MTA to conduct structural repairs to the line, including steel and concrete work; the project was to be completed in September 2024.

The MTA would operate a shuttle bus between Norwood–205th Street and the 4 train at Mosholu Parkway station.

The extension, called "Route 106", was proposed to run elevated over Bronx Park in the lower-deck of a viaduct connecting 205th Street and Burke Avenue.