Mike has posted beautifully spooky pictures of an abandoned subway tunnel (one that might "grow up" and be part of the Second Avenue Subway - it was built as part of the 1970s effort for the line) at Satan's Laundromat. The photos are in two groups: First, the tracks and tunnels themselves and then the stairs and hallways leading to them. Mike writes, no teases, "Accessing prohibited sections of the subway can be hazardous or fatal. Do not attempt it."
Satan's Laundromat also has links to LTV and their various subway tunnel explorations. We love LTV's FAQ:
LTV knows NYC like the backs of our significant other's asses. Active since the tiny days of the late 70's and officially founded in the fabulous 1980's, we are NYC's longest running exploration team. We were here long before "UE" was popular, and we'll be here long after the trendies fuck off.
Thank goodness for that! Gothamist on the Second Avenue Subway.