Evergreen explainer
What is an SPMT?
A self-propelled modular transporter (SPMT) is a multi-axle platform vehicle designed to move extremely heavy and oversized loads — from offshore jackets to nuclear reactor vessels to stadium roofs.
The basics
An SPMT consists of a series of axle lines — each carrying a row of pendulum axles — connected to a power pack unit (PPU) that provides hydraulic power for the suspension, steering and drive. Individual modules (typically 4 or 6 axle lines each) can be coupled longitudinally and side-by-side to form combinations of hundreds of axle lines for the heaviest lifts.
Key characteristics
Unlike conventional trailers, every axle line in an SPMT is hydraulically connected in groups. This means the suspension actively levels the cargo deck even on uneven ground — the key reason SPMTs can carry loads that would destroy any conventional vehicle. The hydraulic system also provides all-wheel steering, allowing incredibly tight turns for a vehicle carrying thousands of tonnes.
How many axle lines do you need?
The required number of axle lines depends on cargo weight, the allowable ground bearing pressure at the site, the technical rating of the equipment, and (for public roads) the permit axle-load limit. Use the SPMT World calculator to run an indicative check based on the DNV-validated calculation spec Rev B.
Manufacturers
The main SPMT manufacturers are TII Scheuerle, Goldhofer, TII Kamag, Cometto, and several Chinese manufacturers. The specifications page will host verified technical data for each model once datasheets have been confirmed.
Who uses SPMTs?
SPMT operators worldwide own fleets ranging from a few dozen to over 4,000 axle lines. Browse the company directory or the fleet map to find operators near you.