Three hundred army supply wagons stretched across the open prairie, carrying tons of food, weapons, and ammunition, enough to sustain 2,800 soldiers for about four months. Because these supplies were both vital and vulnerable, they became a central concern for both commanders. General Taylor placed the wagons behind the battle line, kept his infantry close to the train, and relied on his artillery for defense. Under heavy American cannon fire, Mexican General Arista ordered repeated cavalry charges in an effort to destroy the enemy’s supply train. Officers later emphasized that the army’s four-wheeled wagons, each drawn by six mules and carrying about 2,000 pounds, were essential in a country lacking supplies, making both battle and protection of the train simultaneous objectives.