A heavy hauler is a very large transporter for moving oversize loads too large for road travel without an escort and special permit.
A heavy hauler typically consists of a Ballast Tractor and a hydraulic modular trailer. Some trailers may have independently steerable wheels, and several might be towed by one or more tractor units in a train.
Self-propelled modular transporters (SPMT), some featuring a dozen or more self-steering axles with scores of rubber tires to spread out a load, are increasingly being manufactured. Working in coordinated teams, heavy haulers are able to carry loads exceeding 100 tons.
Applications
In some cases, a heavy hauler is designed and constructed to move a particular load on a one-off or short-term basis. An example is the self-propelled antenna transporter for the ALMA radio telescope project, a 130-tonne (130-long-ton; 140-short-ton) 28-wheeled rigid vehicle designed to carry and place 115-tonne (113-long-ton; 127-short-ton) radio telescope antennas up a mountain to an altitude of 5,000 m (16,400 ft).[1] Girder bridge (lowboy) trailers are another specialist heavy hauler, specifically for the transport of large power transformers.[citation needed]
The term "heavy hauler" may also be used to refer to off-road dump trucks and ore carriers used in mining and construction with capacities up to 400 tonnes (390 long tons; 440 short tons), or an airplane that has been especially constructed for moving heavy materials.[2]
There are some shipbuilding companies using SPMT for carrying ship parts and constructing ships in China. They have saved millions of dollars formerly spent transporting loads using gantry cranes.[citation needed]