(FORTUNE Magazine) – At 70, while other men his age were trying to dodge the express train to Eternity, W. Graham Claytor Jr. became chairman of Amtrak. Now, seven years later, both he and the federally subsidized passenger railroad are looking better than ever. Thanks to vigorous cost cutting and aggressive marketing, Amtrak is generating enough cash to cover 72% of its $1.7 billion budget, up from 48% in 1981. Claytor wants revenues to cover 100% of the operating budget by 2000. He may just stick around to see it happen. ''I'm not slowing down,'' says the feisty boss. ''I'll stay here as long as my health is good.'' After practicing law for two decades, Claytor joined Southern Railway as its head lawyer in 1963 and became CEO four years later. He retired from Southern in 1977 and served as Secretary of the Navy and deputy defense secretary in the Carter Administration before boarding Amtrak. His brother Robert, 67, is a railroad man too: He was CEO of Norfolk & Western, which merged with Southern in 1982, then head of Norfolk Southern till he retired in 1987. How does Claytor keep his fires stoked? With several invigorating interests, including gardening, antique toy trains, and water-skiing. Yes, the 77-year- old Claytor still water-skis, within limits. ''I can't get up on one ski anymore,'' he ruefully admits.