Gantry Crane Explained: Types, Uses and Lifting Safety

A gantry crane is a bridge-type crane whose horizontal beam is carried on legs that run on rails or wheels at ground level. Unlike an overhead crane, it does not need a building structure to support it: the legs do that job. Gantry cranes are used in precast concrete yards, steel fabrication shops, ports, shipyards and on infrastructure projects where heavy, repetitive lifts are needed over a defined area.

This guide explains how gantry cranes work, the main types, where they appear on construction projects and the safety and regulatory framework in Singapore, including the Workplace Safety and Health (Operation of Cranes) Regulations 2011 and the Singapore Standard for gantry and overhead cranes.

What a gantry crane is

The crane has four main parts:

The bridge or girder: one or two horizontal beams spanning the working area.
The legs: vertical frames at each end that carry the bridge.
The end carriages or travel units: wheel sets at the base of the legs that run along rails or on tyres.
The trolley and hoist: a carriage that travels along the bridge, carrying the hoist that raises and lowers the hook.

The three motions, long travel of the whole crane, cross travel of the trolley and hoisting, let the hook reach any point within a rectangular area. That makes the crane well suited to yards where materials are stored, handled and loaded in an organised layout.

The relationship to the overhead crane is close. An overhead crane runs on rails mounted high on a building’s columns; a gantry crane carries its own rails down to the ground. Our sibling guide to the overhead crane covers the building-supported version.

Main types of gantry crane

Full gantry cranes

Both ends of the bridge are supported on legs running on ground rails. These are the typical cranes of precast yards and outdoor stockyards.

Semi-gantry cranes

One end runs on a ground rail via a leg, while the other runs on an elevated rail attached to a building or wall. Semi-gantries are used where an existing structure can support one side, saving a leg and freeing floor space.

Rail-mounted and rubber-tyred gantries

Rail-mounted gantries run on fixed tracks and suit permanent yards. Rubber-tyred gantries run on tyres and can move between areas or be repositioned, common in container terminals and some precast yards.

Single-girder and double-girder

Single-girder cranes have one bridge beam with an underslung hoist and suit lighter loads and spans. Double-girder cranes have two beams with a trolley running on top, giving greater capacity, span and hook height.

Portable and launching gantries

Small portable gantries, on castors or wheels, are used in workshops and for maintenance. At the other extreme, launching gantries for bridges and viaducts are specialised erection systems that place precast segments or beams, designed as temporary works for each project.

Where the gantry crane is used in construction

On a typical building site, gantry cranes are uncommon because tower and mobile cranes cover the site more flexibly. They appear most often behind the scenes:

Precast yards and factories: lifting reinforcement cages into moulds, demoulding and stacking precast elements, and loading trucks. Our guide to precast concrete construction explains the production process.
Prefabricated modules: handling volumetric modules in factories that produce them for PPVC construction.
Steel fabrication: moving plates, sections and assembled members through cutting, welding and painting.
Infrastructure: segment handling in casting yards, tunnelling shafts and viaduct erection.

Structural and foundation considerations

A gantry crane’s rails need foundations designed for the wheel loads, which are concentrated and move with the crane. Differential settlement of the rails can cause the crane to skew, bind or derail, so rail foundations are usually continuous reinforced concrete beams or slabs on suitable ground or piles. The crane structure itself is designed for vertical loads, horizontal braking and acceleration forces, skewing forces and wind, including storm conditions where the crane must be secured.

Outdoor gantry cranes are vulnerable to wind. When parked, they should be secured with rail clamps, storm anchors or tie-downs, and operation should stop when wind speeds exceed the manufacturer’s limit. Singapore’s sudden squalls make this a practical concern rather than a theoretical one.

Singapore lifting and safety requirements

Regulations and standards

The Operation of Cranes Regulations define a crane broadly and apply to any workplace in which a crane is in use. The responsible person must establish a lifting plan and appoint a lifting supervisor, with the required training and at least one year of relevant experience, before any lifting operation involving a crane. Riggers and signalmen are appointed for the lift. The Singapore Standard SS 497 is the code of practice for the design, safe use and maintenance of gantry cranes, overhead travelling cranes and monorail hoists.

Registration and examination

Gantry cranes are lifting machines that must be registered with MOM before use and tested and examined by an Authorised Examiner, an MOM-approved Professional Engineer. Under MOM’s revised requirements effective 12 September 2025, fixed cranes and other lifting machines are examined at least every 12 months, with an overload test required at first registration or re-registration. Lifting gear, such as slings, shackles and hooks, must also be examined periodically, by an Authorised Examiner or, under the revised rules, a competent person appointed by the occupier.

Common hazards

People struck or crushed by the travelling crane, particularly at the legs and wheels, where travel warnings, rail guards and clear walkways are needed.
Loads swinging or falling during demoulding, when suction or bond between concrete and mould can create a sudden load spike.
Collisions between two cranes on the same rails, controlled by anti-collision devices and limits.
Working under suspended loads, which should be prohibited by layout and procedure.

The WSH Council’s Code of Practice on Safe Lifting Operations includes a sample checklist for overhead travelling cranes that is also a useful reference for gantries. If you are designing rail foundations or reviewing a yard layout, our consultancy can help.

Frequently asked questions

What is the difference between a gantry crane and an overhead crane?

A gantry crane is supported on its own legs that run on ground-level rails or tyres, while an overhead crane runs on elevated rails carried by a building’s columns or structure.

What is a semi-gantry crane?

A semi-gantry has a leg running on a ground rail at one end and an end carriage running on an elevated rail attached to a building or wall at the other.

Where are gantry cranes used in construction?

They are used mainly in precast yards and factories, steel fabrication shops, module factories, casting yards and infrastructure projects rather than on typical building sites.

How often must a gantry crane be examined in Singapore?

Under MOM’s revised requirements from 12 September 2025, fixed cranes and other lifting machines are tested and examined by an Authorised Examiner at least every 12 months, after first registration with MOM.

Which Singapore Standard covers gantry cranes?

SS 497 is the code of practice for the design, safe use and maintenance of gantry cranes, overhead travelling cranes and monorail hoists.

Designing crane rail foundations or planning a precast yard? Talk to our consultancy or get in touch.