The term 'haulage unit' is a job description for a TON, which is a unit of measurement that is equal to 2, 000 pounds. A TON is often used to measure the weight of large objects, such as vehicles or cargo. Haulage units are responsible for transporting these heavy items from one place to another. They must ensure that the items are safely and securely loaded and unloaded, and that they are delivered on time.