Dirt from shoes. Snow and rain and yuck. Spilled drinks and sticky gum.

Metro's burgundy carpets are evolving to a bland brown thanks to a daily dose of gross. And now Metro's top officials are thinking about ripping them out and replacing them with a speckled black, hard surface.

"It was a great idea when they built the system to put carpet in the cars. ... People take longer trips, and they want to have more of a commuter train feel instead of a subway feel," Metro General Manager Richard Sarles told the D.C. Council. But despite periodic shampooing, "[The carpet] just, as we all know, it doesn't do too well."

Sarles said the new waterproof surface has already been tested.

"If the test is fully successful, you may see us move away from carpet in the now-existing [rail car] fleet," he said. "But that decision hasn't been made yet."

Metro also is expecting its first cars from the new 7000 series to arrive in the summer of 2015, and the last to arrive in 2017, Sarles said. The snazzy new cars will feature rubber, no-slip floors, better safety mechanisms and signs to let riders know where their train is and which stations are coming up.

"If we arrange it right, we might be able to tell you what restaurants are in the neighborhood," Sarles said.

The 7000 series will help Metro have enough rail cars to run the new Silver Line, which is scheduled to open to Reston at the end of the year, officials say. The new cars also will replace Metro's oldest rail cars, the 1000 series, which national safety officials have criticized for collapsing during crashes. The nine people who died on the Red Line in 2009 were in a 1000 series car.

Sarles said Metro also may replace its cantankerous 4000 series rail cars with more 7000 series cars as well, since the 4000 group breaks down often.

But that wouldn't be anytime soon, he said.

"You wouldn't see those cars until the end of this decade," he said.