Originally, the southern terminal of the G crosstown local ("GG" in the initial lettering scheme of the IND subway) was at Church Avenue, not at Smith & 9th Streets. South of Church Avenue, the line expands to two subterranean levels with four tracks on each level. When it was opened in the 1930s, the track configuration was similar to what still exists in the "hole" east of the 179 St terminus at the Queens end of the F. The four tracks on the upper level were to feed into a future extension of the IND subway, while the four tracks on the lower level were to permit relays and lay-ups for the G. In the 1950s, when it became clear that the funding for subway expansion to replace the old Culver elevated would not be forthcoming, the TA opted instead to connect the four upper level tracks to the existing elevated structure so that trains on the South Brooklyn IND could continue all of the way to Coney Island (this is the current F route). The G continued to terminate at Church Avenue until the 1970s. During the fiscal crisis, the MTA eliminated service on the express tracks between Bergen Street (lower level) and Church Avenue, which made it possible to cut the G back to Smith & 9th Streets; the G now relays in the vicinity of the 4th Avenue Station on what were built as express tracks. Like many "temporary" service cuts in the 1970s, this one became more-or-less permanent. Increasing ridership on the Brooklyn F in recent years has led to talk of reintroducing express service (possibly by extending the V into Brooklyn), which would require the extension of the G back to Church for operational reasons. With the current MTA budget woes, however, these proposals have been shelved. It's too bad, since the configuration of switches in the vicinity of 4th Avenue only permits one train to relay at a time, which contributes to erratic service on the G line.
