A specialized flatbed trailer with very low deck height for oversized industrial equipment.
Detailed Definition
A lowboy trailer has a deck that drops down behind the gooseneck and sits close to the ground, with a raised section over the rear axles. The low deck lets taller equipment, such as excavators, dozers, transformers and large machinery, stay within legal height limits. Many lowboys have a removable gooseneck (RGN) so the front can detach and equipment can be driven on. Lowboys are compared with the flatbed and the step deck, which sit higher.
Lowboy, step deck and flatbed compared
A flatbed has a single flat deck and suits loads that fit within legal height on a standard deck. A step deck has a lower rear deck for somewhat taller freight. A lowboy drops lower still and is built for heavy, tall equipment, often with extra axles to spread weight. Deck lengths, heights and capacities vary by trailer, so carriers state them per unit. Palletized freight rarely needs a lowboy; it is mainly used for machinery and oversized loads. Lowboy capacity is often quoted in tons and depends on axle count and spacing.
Planning a lowboy move
- Give the carrier accurate dimensions, weight and photos, including attachments and the location of lift and tie-down points.
- Oversize or overweight loads need permits from each state traveled and may need escorts or route restrictions.
- Cargo must be secured under the federal cargo securement rules in 49 CFR Part 393, which include specific requirements for heavy equipment and machinery.
- Plan loading: drive-on, crane or forklift, and whether ramps or a detachable gooseneck are needed.
- Check site access, since long, low trailers can ground out on steep driveways or rail crossings.
Related Glossary Terms
Frequently Asked Questions
What is an RGN lowboy?
RGN stands for removable gooseneck. The gooseneck at the front of the trailer can be detached, often hydraulically, and the front of the deck lowered to the ground to act as a ramp. Equipment can then be driven or winched on from the front, which suits tracked machines and loads too heavy for a crane or forklift. Fixed gooseneck lowboys load from the rear using ramps instead.
Do lowboy loads always need oversize permits?
No. A lowboy is often chosen so that a tall load stays within legal height without a permit. Permits are needed when the loaded vehicle exceeds legal width, height, length or weight limits, which come from federal rules on certain highways and from each state. Because limits differ by state and route, the carrier or a permit service should check every state on the route before the move.