For transport of undetachable, oversized and overweight cargos, we offer a combination system, heavy-duty hydraulic modular trailer. This modular system provides almost unlimited possibilities to solve simple as well as complicated transport tasks. The individual platform modules can be combined in longitudinal and lateral direction. It possesses some advantages, such as adjustable platform, axle load, small turning radius, easily moving backward, and so on. Adjustable body keeps the horizontal level while running on the upper and lower ramps, and guarantees the running vehicle is smooth-going, safe and steady.