containers have also been designed. Post-Panamax cranes weigh approximately 800–900 tonnes, while the newer-generation super-post-Panamax cranes can weigh 1,600–2,000 tonnes. The largest Super-post-Panamax cranes have an outreach of 26 container rows. Operation The crane is driven by an operator who sits in a cabin suspended from the trolley. The trolley runs along rails located on the top or sides of the boom and girder. The operator runs the trolley over the ship to lift the cargo, usually containers. Once the spreader locks onto the container, the container is lifted, moved over the dock, and placed on a truck chassis (trailer) to be taken to the storage yard. The crane also lifts containers from chassis on the dock to load them onto the ship. Straddle carriers, sidelifts, reach stackers, or container lorries then manoeuvre underneath the crane base and collect the containers, rapidly moving them away from the dock and to a storage yard. Flatcars or well cars may also be loaded directly beneath the crane base. Power A crane can be powered by two types of power supply: a diesel engine–driven generator located on top of the crane or electric power from the dock. The most common is by electric power from the dock (also known as shore power). The voltage required may range from 4,000 to 13,200 volts. History Cranes were used in harbors starting in the Middle Ages (see crane: harbor usage and list of historical harbour cranes). Modern inter-modal containerization emerged in the mid-1950s from transport strategies developed in the Second World War and the Korean War, and the development of specialized cranes paralleled developments in containerization. The first container crane was built by Paceco (formerly the Pacific Coast Engineering Company) for Matson at the Encinal Terminal in Alameda, California in 1959. See also Gantry crane Rubber tyred gantry crane Straddle carrier References External links Cranes (machines) Intermodal containers Port infrastructure