7, L Trains City's Cleanest

Eighty-eight percent the cars on the L line were rated as clean, compared to just 61 percent the last time the survey was taken two years ago.

The 7 train saw even more dramatic improvement - it jumped from the fourth dirtiest line to tie for second cleanest. The two lines got special treatment from the Metropolitan Transportation Authority, which assigned round-the-clock cleaners to both lines.

Gene Russianoff, of the Straphangers Campaign, says the survey - named for the Yiddish word for dirt - draws attention to an important issue.

RUSSIANOFF: We think the riders really care about the cleanliness of subway cars and because we think transit officials can do better.

REPORTER: The Q and E lines were rated as the dirtiest.