The IND Crosstown line, better known as the G line, is often characterized as a lonely, underutilized line. The reality is that it is a relic of a different New York. It is a line that was supposed to have been interwoven with other lines (planned for the IND Second System) branching through Manhattan, Brooklyn, and Queens, the plans for which never came to fruition.

As with nearly every single subway line built by the IND, the Crosstown line was built with a number of provisions for future expansion, in order to provide for easier connections to the planned lines. These include provisions for a Lafeyette Av line, Myrtle Av line to the Rockaways, and a Stuyvesant Av to Utica Av line. The latter two lines would have run through the S 4th St hub (better known as Underbelly), a station shell provision for which was built above the Broadway station.

The Lafayette Av line would have run from Manhattan (possibly as an extension of the planned 2nd Av line) via new crossriver tunnel, connecting to the G at or about Hoyt/Schermerhorn Sts and running up the Lafayette Av portion of the line. Past Bedford/Nostrand Avs where the current Crosstown line curves North onto Marcy Av, the Lafayette Av line would have continued East. Provisions for this extension were built at Classon Av and Bedford/Nostrand Avs, with a space for a middle track built at Classon Av (intended for layups/storage for short runs), and 2 tail tracks East of Bedford/Nostrand Avs. These tail tracks sink beneath the Crosstown line and head a short distance east before dead ending at bumpers.

Three of these four provisions can be seen simply by standing on station platforms. The ones at Classon Av and Bedford/Nostrand Avs are pretty straightforward. The tail tracks east of Bedford/Nostrand are dark, damp, and dirty, as is the S 4th St station shell. Today, the middle track and tail tracks at Bedford/Nostrand are occasionally used for short term train storage, especially for garbage collection and other work trains.