A ballast tractor is a specially weighted tractor unit of a heavy hauler combination. It is designed to utilize a drawbar to pull or push heavy or exceptionally large trailer loads which are loaded in a hydraulic modular trailer. When feasible, lowboy-style semi-trailers are used to minimize the height of a load's center of mass. Typical drivetrains are 6×4 and 6×6, but 8×6 and 8×8 are also available. Typical ballast tractor loads include oil rig modules, bridge sections, buildings, ship sections, and industrial machinery such as generators and turbines.
Only a handful of manufacturers produce dedicated ballast tractors. Extra-heavy-duty chassis versions of mass-production tractor units are fitted with drawbar hitches and a separate ballast box as an alternative. These units are classified as N3 Category of large goods vehicle. Ballast tractors can be traced back to the 1940s when heavy haulers from the UK started employing purpose-built Scammell Showtracs, a short wheelbase 4×2 ballast tractor.[1][2]
Increasingly, remote-controlled, self-propelled modular transporters (SPMT) are being employed in traditional ballast tractor/trailer roles.
- ^ "Roll up, roll up... | 7th June 2012 | The Commercial Motor Archive". archive.commercialmotor.com. Retrieved 14 June 2023.
- ^ "No. 3 | Vehicles". Carters Steam Fair. Retrieved 14 June 2023.