Context: Walden was the result of Thoreau's voluntary semi-isolation between 1845 and 1847, when he lived in a small hut of his own construction at Walden Pond, near the village of Concord, Massachusetts. Thoreau undertook this life so he could live in nature, with an uncluttered existence that would give him the time and opportunity to think clearly, deeply, and long about man and his condition. In this chapter of Walden, Thoreau writes of his surroundings, devoting a fairly long passage to the Fitchburg Railroad and its trains, which he heard pass at a distance from his hermitage at Walden Pond. He sees that the advent of the railroad has almost made new men of some, even to making them courageous, or prompt. Though he was a transcendentalist, Thoreau was also a man interested in the world as at least foreshadowing a better existence, so he can write with appreciation, as well as criticism, for the things of this life. In writing about the railroad, he comments on the men who man the railroad's snowplows in the wintertime:
. . . I am less affected by their heroism who stood up for half an hour in the front line at Buena Vista, than by the steady and cheerful valor of the men, who inhabit the snow-plow for their winter quarters; who have not merely the three-o'-clock-in-the-morning courage, which Bonaparte thought was the rarest, but whose courage does not go to rest so early, who go to sleep only when the storm sleeps or the sinews of their iron steed are frozen. On this morning of the Great Snow, perchance, which is still raging and chilling men's blood, I hear the muffled tone of their engine bell from out of the fog bank of their chilled breath, which announces that the cars are coming, without long delay, notwithstanding the veto of a New England northeast snowstorm, and I behold the plowmen covered with snow and rime, their heads peering above the mould-board which is turning down other than daisies and the nests of field-mice, like bowlders of the Sierra Nevada, that occupy an outside place in the universe.