The new style of hard flooring is visible in the interior design for the 7000 series cars. (Robert Thomson/The Washington Post)

You can’t accuse Metro of rushing into changes in its rail cars. The first time I saw a rail car with hard flooring substituted for the smelly old carpet was in April 2008, when transit officials showed off several test cars parked at the Reagan National Airport station.

Those test cars, part of the 6000 series, rolled around the Metrorail system for years before the transit authority announced that the next generation, the 7000 series now under construction, would go with a very different style of interior, including hard flooring rather than carpets.

On Thursday, Metro announced that it also will replace the carpet on part of the current rail fleet, the 5000 and 6000 series cars. The installation of this slip-resistant flooring should happen gradually over two years, the transit authority said.

Back in the mid-1970s when Metro opened, carpets and cushy seats seemed like a good idea. Metro was part of a new generation of rail transit systems, built at the height of the auto age. Planners thought it was important to offer commuters an attractive and familiar alternative to their cars.

As with other parts of the system, like the escalators, the early planners never considered that the equipment would get old. Metro officials say the hard flooring doesn’t absorb dirt or spills. The carpet not only absorbs them, but also resists giving them up.

General Manager Richard Sarles said the new flooring will provide a “modern look and feel” to the rail cars.

Transit officials also note a practical goal in the program: The new flooring should last longer than carpet before needing replacement.