From Halopedia, the Halo wiki
Welcome Wagons are small container-like craft capable of moving up and down a space elevator's strand, transporting large numbers of civilian personnel offworld or down from an orbiting platform. Harvest possessed 237 Welcome Wagons, which were used to evacuate the colonies population when the Covenant attacked the planet. Only one-sixth survived the evacuation, the rest were destroyed by the Covenant forces.
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