Hydraulic modular trailer

A hydraulic modular trailer (HMT) is a platform trailer unit that features swing axles, hydraulic suspension, independently steerable axles, two or more axle rows, compatibility to join two or more units longitudinally and laterally, and uses a power pack unit (PPU) to steer and adjust height. These trailer units are used to transport oversized loads, which are difficult to disassemble and are overweight.

Source: Wikipedia — Hydraulic modular trailer (CC BY-SA 4.0)