Heavy hauler

For the large dump truck, see haul truck.
Two MAN SE ballast tractors pulling and one Mercedes pushing a 100,000 kg (220,000 lb) transformer on 10-axle lowboy trailer
ALMA antenna in transit on a self-propelled modular transporter

A heavy hauler is a very large transporter for moving oversize loads too large for road travel without an escort and special permit.

A Mammoet SPMT moves a large ship section.

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.