“What’s coal?” McQueen would demand oracularly. “It’s carbon and oxygen and hydrogen with a dash of nitrogen, ain’t it? Well, then, what are you talking about? Coal _ain’t_ just coal, some of it’s mostly slate. Two hundred and ten pounds all the way, all the time, with the grate bars cluttered with that, huh! What?” No purchasing agent that had ever hit the division had been quite able to satisfy McQueen with the brand of the commodity that was supplied in accordance with the requisition orders that he drew. And so, day in and day out, big 802 puffed her way through the mountains, and McQueen, in the cab, absorbed coal statistics, coal data, coal everything, with an avidity, a thoroughness, and a masterliness of detail, that would have put some noted geologists to shame and given the rest a run to hold their rights on the marked-up schedule. Up at headquarters--when things were running smoothly and McQueen was behaving himself with no scores chalked up against him on the time-card--they treated his hobby as a joke. So that when his whistle boomed out of the gorge to the westward, or shrilled across the cut to the eastward, followed a moment afterward by the sight of the big, flying mogul with her string of slewing dark-green coaches, the staff on duty at Big Cloud would lean from the upper windows and watch the Limited as she shattered the yard switches with a roar--watch as, with a hiss of the air and the grinding of the brake shoes as they sparked the tires, she would draw up, panting, at the platform, and the big engineer would swing himself from the cab for an oil around. Then the badinage flew thick and fast while McQueen swabbed his hands on a hunk of waste and punctuated the remarks with squirts from his long-spouted can as he filled the thirsty oil cups. So the big fellows laughed and joked, and the Brotherhood chaffed him unmercifully. If anyone had asked McQueen what had started, let alone caused him to exhaust the subject of coal with such painstaking and conscientious insistence, he couldn’t for the life of him have answered. It had started--just started, that’s all--and, fascinating him, had pursued its insidious advance unchecked and unquestioned--that is, unquestioned until one morning when Clarihue, the turner at the Big Cloud roundhouse, kind of jerked him up a little on the proposition. “You’re against the red, you and your coal, Mac, all right, all right,” Clarihue chuckled, as the engineer came in to sign on for the day’s run. McQueen was patting 802’s slide bars affectionately. “How’s that?” he asked. “Oil!” “Oil?” repeated McQueen, puzzled. “Sure thing! No more coal--no more slate--no more cinders--you touch her off, and there you are! You’ll have to cut out the coal and plug up on oil, Mac.”