From The Urban Dictionary:
G-Train: Annoying, unreliable and/or weak; a waste of time; similar to the G train line in Brooklyn.
Can be shortened to just "G" or "G-shit" or replaced by cupping the fist into a G-shape.
"You going to Dee's party? "
"Nah, that shit's G-train, son."
The only person I ever knew who rode the G train was my grandfather back when it was still the "GG" and back when I guess people actually lived where the G train went.
Now the poor old G train finds itself emasculated; serving as a synonym for "wack" for the Urban Dictionary.
To most Brooklynites the G train of today is as elusive and as abstruse as Nessie, the the legendary Loch Ness Monster.
I stumbled upon this glorious blog called The Legend of the G Train which details various G Train spottings, murky eyewitness accounts, dubious folklore and fables as well as very rare photos of the G Train in its natural habitat!
People go on African safari to see the Big Five; in Brooklyn people risk their lives just for a glimpse of this evasive Brooklyn–Queens Crosstown Local.
two of Brooklyn's most mystifying icons in one shot!
The Legend of the G Train advises:
"While the search for the G train can be unrewarding at times, it is important to keep your spirits up and not allow fakers to sway you from your task. Be skeptical, be critical, and most importantly, be alert!"Check out the blog. They do a wonderful job attempting to corral all the evidence and mythology about this fascinating and confounding legend.
and there she goes, into the cold, grey night