 Starting now, train operators are using what they call automatic door operations on the blue, orange, silver, yellow and green lines. Metro says the technology allows doors to open within three to five seconds after the train stops on the platform. While train doors will open automatically upon arrival, operators will still close the doors manually when they depart. Metro previously launched an auto doors on the red line last December. It says the time saved per stop is about 10 seconds. Coming up in money news on WTOP.