Radial locks have a curved gate like a segment of a cylinder. A rope and pulley system with counterweights brings the gate up out of the water so barges can pass underneath. The old lock used a hand-turned wheel connected to gears, which allowed one person to lift the 4.5tonne gates single-handedly - but rather slowly. The new lock will use an hydraulic engine to do the same job.
This animation by KGAL shows the radial lock gate lifting up, and then dropping back down again.