Who turned on the lights?Even scurrying commuters have noticed that New York's Grand Central Terminal, after a detailed and delicate face-lift, is positively beaming. Brass and glass have been polished. Gone from marble walls and balustrades are layers of grime that had accumulated since 1913, when the station opened. Most dramatic is the revelation of the constellation ceiling's true color: bright robin's-egg blue. (You don't remember the pre-cleaning shade?A tiny dirty patch in the northwest corner was preserved for contrast.

New fiber-optic lights in the "stars" of the zodiac will soon twinkle over diners and drinkers coming to the Beaux-Arts landmark to catch everything but a train. Due to open in early '98 is a David Rockwell-designed steak house, bringing white tablecloths to the balcony overlooking the main concourse. By this time next year, every other inch of the terminal will be just as dazzling, from a new entrance on Lexington Avenue housing a fresh food market (Need cheese?Bread?A leg of lamb?) to a lower-level dining concourse (Hungry for caviar?Tabbouleh?Tomato soup?). Grand Central, driver, and step on it.