Types of vehicles
A heavy hauler usually consists of flatbed trailer units with multiple wheels (which may be independently steerable), pulled by a heavy tractor unit. Several trailers might be towed by one or more tractor units. The ability to carry loads of 2000 tons is not unusual.
The term "heavy hauler" may also be used to refer to an airplane that has been especially constructed for moving heavy material, or to off-road dump trucks and ore carriers used in mining and construction with capacities up to 400 tonnes.
In some cases a heavy hauler is designed and constructed to move a unique or particular kind of load on a one-off or short-term basis. An example is the antenna transporter for the ALMA radio telescope project, a 130-tonne 28-wheeled rigid vehicle designed to carry and place 115-tonne radio telescope antennas up a mountain to an altitude of 5000 m (16,500 ft).
Typical loads moved by heavy haulers under escort on highways include giant boilers and pressure vessels used in the chemical industries, industrial plants, prefabricated sections for construction projects, giant power transformers, turbines, and houses (generally made of timber).
When a heavy hauler moves an oversize load on a highway, as well as being escorted by vehicles with flashing lights to warn other road users to keep out of the way, they may be accompanied by vehicles to move overhead obstructions such as power lines and cables out of the way.