Out came the coal with a clatter; out came the depot stuff with a sheet of flame through the goat's flues--shot here, shot there, shot yonder--flying down this spur and down that and the other, like stones from a catapult; and the tough-connected, smut-faced, blear-eyed yard engine coughed and snorted and spit a shower of sparks and soot and cinders up into the Christmas air. She darted and dodged and jerked, and backed up and down and across the lead, and never for a fraction of a second took her eye off Shockley's lamp. Shivering and clanging and bucking with steam and bell and air, but always with one smoky eye on Shockley's lamp, until Twenty-three was wrecked clean to the caboose, and the switch engine shot down the main line with the battered way-car in her claws like a hawk with a prairie dog. Then there was only the westbound freight, Fifty-five, to make up with the Fort Rawlins stuff and the Cherry Creek steel, which was "_rush_," and a few cars of ties flung on behind on general principles. It was quick work now--sorting and moving the bridge steel--half an hour for an hour's work, with the north wind waking at the clatter and sweeping a bank of cloud and sand across the valley. Shockley and Chris and the goat crew put at it like black ants. There was releasing and setting and kicking and splitting, and once in a while a flying switch, dead against the rubrics; and at last the whole train of steel was in line, clean as the links of a sprocket, and ready to run in on the house-track for the caboose. For that run Chris set the east house-track switch, crossed the track, and swung a great circle with his lamp for the back. To get over to the switch again, he started to recross the track. In the dark, his ankle turned on a lump of coal; he recovered lightly, but the misstep sent his other foot wide, and with a bit of a jolt Rubedo's new shoe slipped into the frog. Up the track he heard a roll of stormy coughs from the engine gathering push to shove the string of flats down. They were coming towards him, over the spot where he stood, on his signal; and he quietly tried to loosen his heel. The engine's drivers let go, and she roared a steaming oath, and Chris could hear it; but he was glad, for his heel would not work quietly out of the frog; it stuck. Then the engineer, unruffled, pulled at his sand lever, and his engine snorted again and her driver tires bit, and slowly she sent the long train of steel down on Chris's switch; he heard the frosty flanges grinding on the face of the rails as he tried to loosen his foot.