The cars are being produced in Lincoln, Neb., and production is expected to begin this winter.
Riders said Wednesday that they would welcome some changes.
Thelma Murray-Fisher, 65, who has been traveling on Metro since it opened, said she'd appreciate more space to hold on during busy rush-hour times. Tim Wood, a George Washington University professor, said the electronic signs would be especially helpful for tourists who are always trying to get to the Smithsonian stop. And Sofia Castillo, 30, a law student at American University, said a replacement for the often-stained carpet made sense to her. Castillo said she couldn't think of any other improvements, but as she neared her stop she looked out the window.
"Is that Metro Center?" she said. "I think so."