The evidence has piled beside turnstiles and beneath benches, along subway platforms where riders found nowhere else to place their coffee cups or apple cores and on the tracks where tattered newspapers and crushed bottles seem to have taken up permanent residence.

Yet despite some riders’ resourceful disposal methods since trash cans were removed from two subway stations last year, the Metropolitan Transportation Authority says the counterintuitive plan has worked: trash hauls have decreased, it said, and the stations are cleaner.

As a result, the authority said, the pilot program has been expanded to eight more stations, including stops at 57th Street in Manhattan, Brighton Beach in Brooklyn, and East 143rd Street in the Bronx.

“I’m actually very intrigued by this,” said Joseph J. Lhota, the transportation authority’s chairman, before urging riders to treat the subway “as you would treat your home.”