It is located just south of the Church avenue F & G line station. It consists of 4 tracks, located below ramps that carry the F train onto the elevated ‘culver line’ elevated viaduct to Coney Island.
When I visited this yard in 2006, it was being used only for laying up (parking) out of service G trains. All 4 tracks were used to store trains. However, on July 5, 2009, G train service was extended from Smith & 9th street to Church Avenue. In order to turn trains from the southbound track to return northbound, one of the inner tracks within the yard is kept clear, allowing a G train to pull in, and reverse back out to the proper platform once the train operator has walked to the other end of the train.
Unlike the 174th street yard, this yard doesn’t seem to have been built as a provision for future subway route expansion, thought it was built during an age were complaints about elevated subway viaducts had grown, so there may have been some thought that the length of the route to Coney Island might someday be placed underground.
*This post supersedes a old site post from July 2006