Overhead & Gantry Cranes

An overhead crane, also called a bridge crane or overhead travelling crane, lifts and moves loads along a bridge that runs on elevated rails. The bridge spans the width of a building or bay, and a hoist travels along it, so the crane can reach any point in a rectangular area below. A gantry crane works on the same principle, but its bridge is carried on legs that run on rails or wheels at ground level, which means it does not need a building structure to support it.

Overhead and gantry cranes are the backbone of materials handling in factories, steel mills, warehouses, precast concrete plants, shipyards and power stations. In construction, gantry cranes are used in precast yards, for bridge and tunnel segment handling, and on large infrastructure sites, while overhead cranes are central to the manufacturing of construction machines and components.

Brief History of Overhead & Gantry Cranes

Travelling cranes running on elevated beams were used in workshops and foundries in the nineteenth century, driven first by hand and later by steam or line shafts. The introduction of electric motors transformed the machine. In 1876, the English engineer Sampson Moore supplied what is generally regarded as the first electric overhead crane, used to handle guns at the Royal Arsenal in Woolwich, London. Electric overhead travelling cranes, often abbreviated EOT cranes, spread rapidly in steelworks, shipyards and heavy engineering plants in the following decades.

During the twentieth century, welded box girders, wire rope hoists, standardised components and pendant controls made overhead cranes more efficient and affordable. Large gantry cranes, sometimes called Goliath cranes, were built for shipyards and dockyards. More recently, variable frequency drives, radio remote controls, anti-sway software and automation have turned many cranes into precise, partly or fully automated handling systems.

How an Overhead or Gantry Crane Works

An overhead crane moves a load in three directions: up and down, along the bridge and along the runway.

Runway. Two parallel rails, mounted on the building columns or on a separate support structure, carry the crane along the length of the bay.
Bridge. One or two girders span the bay between the runway rails. End trucks with wheels at each end of the bridge travel along the runway.
Trolley and hoist. The hoist, usually an electric wire rope or chain hoist, travels along the bridge on a trolley and lifts the load with a hook or other device.
Legs (gantry cranes). In a gantry crane, the bridge is supported by legs that run on ground rails or on rubber tyres. A semi-gantry has legs on one side and a runway rail on the building on the other.
Drives and power. Electric motors move the bridge, trolley and hoist. Power reaches the crane through conductor rails or festoon cables.
Controls. Cranes are controlled from a pendant, by radio remote control or from a cab. Many modern cranes use variable speed drives for smooth movements and anti-sway functions.

Types of Overhead & Gantry Cranes

Single Girder Overhead Cranes

A bridge made of one girder, with the hoist running on its lower flange or alongside it. Light and economical, they are used for light to medium loads in workshops and warehouses.

Double Girder Overhead Cranes

A bridge with two girders and the trolley running on top. Double girder cranes offer higher capacities, longer spans and more hook height, and are standard in heavy industry.

Suspended and Underhung Cranes

Cranes whose end trucks run on the lower flanges of runway beams hung from the roof structure. They keep the floor free and are used for lighter loads.

Gantry and Goliath Cranes

Freestanding cranes with legs running on ground rails. They are used outdoors in precast yards, steel stockyards, shipyards and ports. Very large shipyard gantries are often called Goliath cranes.

Rubber-Tyred and Mobile Gantry Cranes

Gantry cranes on rubber tyres can move freely around a yard. Smaller portable gantries, often made of aluminium or steel, are used in workshops and for maintenance.

Semi-Gantry and Special Cranes

Semi-gantries combine one leg and one elevated rail. Special designs include process cranes for steel mills, polar cranes in reactor buildings and launching gantries used to erect precast bridge segments.

Size Classes

Class	Typical capacity	Typical use
Light	up to about 10 t	Workshops, assembly, maintenance
Medium	about 10 to 50 t	Manufacturing, warehouses, precast plants
Heavy	about 50 to 500 t	Steel mills, power plants, heavy engineering
Very heavy gantries	about 500 t and more	Shipyards, offshore and bridge yards

Figures are indicative. Span and hook height vary widely by application.

Load Handling Devices

The hook is only one of many ways an overhead or gantry crane can hold a load. Common devices include lifting beams and spreaders for long or flexible loads, C-hooks for coils, electromagnets and permanent magnets for steel plate and scrap, vacuum lifters for sheet material and glass, grabs for bulk material and mechanical tongs for slabs and ingots. In precast plants, cranes often use dedicated lifting frames and clutches that match the anchors cast into the concrete elements. Many cranes have two hoists on the same bridge, or two trolleys, so that long loads can be lifted at two points or turned in the air.

Main Manufacturers

Konecranes, a Finnish group with a broad range of industrial and port cranes.
Demag, a German name in overhead cranes and hoists, now part of Konecranes.
ABUS Kransysteme, a German manufacturer of overhead cranes and hoists.
Stahl CraneSystems, a German hoist and crane component specialist.
GH Cranes & Components, a Spanish crane manufacturer.
Columbus McKinnon, an American hoist and handling equipment group.

Main Uses of Overhead & Gantry Cranes

Production and assembly lines in manufacturing plants.
Precast concrete plants and yards, including beams, slabs and tunnel segments.
Steel mills, foundries and steel stockyards.
Shipyards and offshore module yards.
Power stations, hydroelectric plants and maintenance halls.
Bridge construction, where launching gantries place segments and beams.

Planning and Choosing Tips

Duty class. Cranes are classified by how often and how heavily they are used. A crane with the wrong duty class wears out quickly or is oversized for the job.
Span and hook height. The building’s dimensions define the crane. Double girder designs give more hook height in the same building.
Runway structure. For overhead cranes, the building or runway supports must be designed for the crane loads, including braking and lateral forces.
Controls. Radio control gives the operator freedom to stand in a safe position. Anti-sway and positioning functions help with precise loads.
Outdoor use. Gantry cranes outdoors must be designed for wind, with storm anchors and rail clamps.
Inspection and maintenance. Wire ropes, brakes, limit switches and wheels need regular inspection according to local rules.

Safety

The main hazards with overhead and gantry cranes are dropped loads, people struck by moving loads, collisions between cranes on the same runway, falls during maintenance and electrical risks. Operators should keep loads low, avoid carrying them over people, use correct slings and check them before use. Limit switches, overload protection, anti-collision systems and emergency stops are standard safety devices. Maintenance work on the crane requires isolation of power and safe access to the runway. Outdoor gantry cranes must be secured against wind when not in use.

Trends and Technology

Overhead cranes are becoming smarter and more connected. Variable speed drives reduce load swing and wear. Anti-sway and precision positioning software allow faster and safer handling. Remote monitoring and condition-based maintenance track load cycles, brake wear and rope condition. Semi-automated and fully automated cranes are used in warehouses, steel plants and precast factories, where they move loads without an operator on the floor. Energy recovery from lowering and braking movements is also more common. In construction, gantry cranes in precast factories and segment yards are increasingly linked to production planning systems, so that elements are stored, tracked and loaded in the right sequence for delivery to site.

Key Terms

EOT crane: electric overhead travelling crane.
Bridge: the girder or girders spanning the runway.
Trolley: the carriage that moves the hoist along the bridge.
Runway: the rails and beams on which the crane travels.
Goliath crane: a very large gantry crane, typically in shipyards.
Duty class: a classification of how intensively a crane is used.

Frequently Asked Questions

What is the difference between an overhead crane and a gantry crane? An overhead crane runs on rails mounted high on a building or support structure, while a gantry crane stands on its own legs and runs at ground level.

What is a single girder crane used for? Single girder cranes are used for light and medium loads where a simple, cost-effective solution is enough.

Can an overhead crane be installed in an existing building? Often yes, but the building structure must be checked for the extra loads. Otherwise, a freestanding runway structure or a gantry crane can be used.

Are gantry cranes used in construction? Yes, especially in precast yards, tunnel projects and bridge construction, where they handle heavy segments and beams.

How is an overhead crane powered? Most cranes run on electricity supplied through conductor rails along the runway or through festoon cables, with separate motors for hoisting, trolley travel and bridge travel.