Cool Quiz from Gothamist: Where is this?

Mystery transit photo, via Gothamist.

Cool news quiz from Gothamist:  Where is this?   I'm going to guess Flatbush Avenue and Fifth Avenue, in Park Slope, because there was an El there.   But honestly, I've no idea.  To find out the original caption:  click here. (UPDATE..I'm wrong, but only by about a half mile.  It IS Flatbush Avenue, but the corner is Fulton.) -- Andrea Bernstein, TN