It's the N and Q trains' filthy relative, and it's causing the W train to turn over in its grave.
The Straphanger's Campaign's annual Subway Shmutz survey ranks the R train as the dirtiest in New York City.
The 7 train was the most pristine, with a 68 percent rating.
Overall cleanliness declined slightly from last year from 51 percent to 47 percent.
The R was the second worst train in the October survey.