To get the harness on.

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1857.  He could see numerous trains of covered waggons and teams crossing the Mississippi River, and bending their course westward as far as the eye could reach. He also hitched up and joined the trains, and the journey did not seem so arduous as he first anticipated.—Orson Hyde, ‘Journal of Discourses,’ v. 142.

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1870.  He would “hitch up” at once and drive over to Elyria and leave the despatch so it should go the first thing in the morning.—E. E. Hale, ‘Ten Times One is Ten,’ ch. iv. (Century Dict.)

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1878.  At midnight the soldier returned, hitched up at daylight, and, in a steaming state of military wrath, whipped his mules through the forty-three miles to Wingate by sundown.—J. H. Beadle, ‘Western Wilds,’ p. 244.

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