Moving oversized or overweight freight takes more than a larger trailer. Heavy haul transportation utilizes specialized trailing equipment engineered to handle unusual dimensions, extreme weights and complex site requirements. For logistics leaders responsible for coordinating large-scale projects, understanding the equipment options available and when each is used can support better planning, reduce risk and help keep projects on schedule.  

In this guide, we break down the trailer types most commonly used in heavy haul transportation, the freight they typically move and the planning considerations logistics teams should keep in mind when evaluating equipment needs. 

What Is Heavy Haul Transportation? 

Heavy haul transportation involves moving cargo that exceeds standard legal limits for weight, height, width or length. These shipments typically require permitting, specialized trailing equipment and, in many cases, route engineering and escort coordination to move safely and in compliance with state and federal regulations. 

Heavy haul freight spans a wide range of industries, including: 

• Energy & utilities — wind turbine components, transformers, generators 
• Industrial manufacturing — machinery and industrial equipment 
• Construction & infrastructure —heavy equipment, building materials, prefabricated components 
• Aerospace & defense — aircraft components and military equipment 
• Data infrastructure — generators, transformers and cooling equipment 

Why Trailer Selection Matters 

Trailer type affects overall height, weight distribution, axle configuration and ground clearance, all factors that influence permitting requirements, routing options and site access. Equipment that doesn't align with a shipment's dimensions or weight can contribute to delays, added costs or safety concerns. Matching freight to the right trailer configuration from the outset supports a more efficient move and helps manage risk throughout the process. 

For complex heavy haul moves, equipment planning should begin as early as possible. Capacity sourcing, equipment positioning, permitting and route planning can be lengthy processes, particularly when specialized trailers are required. In some cases, trailers may be so large or complex that permits are needed even when moving empty, making equipment positioning a planning consideration of its own. 

Common Heavy Haul Trailer Types and Their Applications 

Flatbeds 

Flatbed trailers feature an open, level deck with no sides or roof, making them well-suited for freight that doesn't require a lower deck height. 

• Commonly used for: construction materials, machinery, equipment 
• Benefit: can be loaded and unloaded from the side or top 

Step Decks 

Step deck trailers include a standard flatbed section at the front and a dropped section toward the rear, creating additional vertical clearance. 

• Commonly used for: taller industrial equipment 
• Benefit: helps shipments stay within legal height limits in many cases 

RGNs (Removable Gooseneck Trailers) 

RGNs feature a detachable gooseneck that allows equipment to be driven directly onto the trailer rather than lifted, simplifying loading for tracked or wheeled machinery. 

• Commonly used for: construction equipment, industrial machinery 
• Benefit: low deck height reduces ground clearance needs 

Stretch Trailers 

Stretch trailers, also called extendable trailers, can be lengthened to accommodate freight that exceeds standard trailer dimensions. 

• Commonly used for: pipe, beams, wind energy components like turbine blades 
• Benefit: extends to fit long, narrow loads 

Lowboys 

Lowboys are designed with a low deck height, typically positioned close to the ground between the axles. 

• Commonly used for: cranes, bulldozers, other construction machinery 
• Benefit: additional clearance for tall, heavy equipment 

Double Drop Trailers 

Double drop trailers include a dropped center section positioned between the front and rear axles, providing additional height clearance for tall cargo. 

• Commonly used for: large industrial equipment and machinery 
• Benefit: accommodates height requirements that exceed what a step deck can handle 

Multi-Axle and Steerable Trailers 

Multi-axle trailers distribute weight across additional axles, while steerable trailers add axles that can turn independently. 

• Multi-axle benefit: helps meet bridge and roadway weight restrictions 
• Steerable benefit: improves maneuverability for tight turns or congested routes 
• Commonly used for: superloads and large industrial components 

Perimeter Trailers 

Perimeter trailers, sometimes called perimeter-frame trailers, use a frame that runs along the outer edges of the deck rather than through the center, allowing freight to sit lower to the ground. 

• Commonly used for: transformers, industrial tanks 
• Benefit: minimizes overall height for tall or heavy loads 

Schnabel Trailers 

Schnabel trailers are engineered to cradle a specific piece of freight within the trailer structure, rather than resting cargo on a deck. 

• Commonly used for: pressure vessels, reactor parts 
• Benefit: highly customized transport solution for extremely large or heavy components 

Matching Trailer Types to Industry Applications 

The table below outlines common industry applications, the freight typically involved and the trailer types often used to support each.