Shipyard gantry cranes are among the most technically demanding lifting machines in any industrial sector. They span widths of 80–170 metres, lift loads of 100–3000 tonnes, and operate in a marine environment that subjects every structural and electrical component to continuous salt-air corrosion. Getting the specification right from the outset determines whether the crane serves the yard reliably for 30 years or becomes a source of unplanned downtime that disrupts the production schedule.

Product Description

What Is a Shipyard Gantry Crane?

A shipyard gantry crane — also called a goliath crane, portal gantry crane, or shipbuilding gantry crane — is a large double-leg gantry structure that spans the full width of a shipbuilding berth, drydock, or block assembly area. It travels on ground-level rails along the length of the working area, covering the entire production zone with its main hoist and trolley.

The crane handles the largest and heaviest lifts in the shipyard: ship hull block sections weighing hundreds of tonnes, engine modules, deck sections, and major structural assemblies. It is the piece of equipment that makes large vessel construction physically possible.

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Main Hoist and Auxiliary Hoist Configuration

Shipyard gantry cranes carry two separate hoist systems on a single bridge:

Main hoist — the primary lifting system, carrying the crane’s rated maximum SWL. Typically a heavy-duty wire rope crab trolley travelling on rails on top of the main girders. Used for all heavy block lifts.

Auxiliary hoist — a secondary hoist with lower capacity but often higher speed. Used for rigging, positioning, and handling smaller items that do not require the main hoist. The auxiliary hoist allows the crane to perform two different lifting tasks simultaneously or in rapid sequence without the main hoist being involved in light accessory work.

The main hoist trolley travels across the full span including the cantilever sections, providing coverage of the entire working area beneath the crane.

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Structural Design: Box Girder and Leg Configuration

The main girder of a shipyard gantry crane is a large box section — fabricated from structural plate into a closed rectangular section with internal stiffening. The box section provides the bending stiffness required for the long spans involved while keeping the structure as light as possible relative to its load-bearing capacity.

Two leg types are commonly used, and the choice affects how the crane handles differential rail settlement or misalignment:

Rigid leg — a fixed-connection leg that transfers all lateral forces from the girder to the rail foundation. Used on one side of the crane.

Flexible (hinged) leg — a leg with a pin connection at the top or bottom that allows limited rotation. Used on the other side of the crane to accommodate differential thermal expansion and minor rail misalignment without inducing stress into the main girder. This rigid + flexible leg combination is standard on large shipyard gantry cranes worldwide.

Technical Parameters

Standard Configuration Overview

Hoisting Performance at Different Load Levels

Speed and performance on a large shipyard crane varies with load. Understanding the speed-load relationship is important for production planning:

Variable frequency drives on all motions provide smooth speed control across the full range — eliminating the step-changes that older contactor-controlled systems imposed and reducing mechanical shock on the rope, drum, and structural connections.

Structural Steel and Environmental Specification

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Application Scenarios

Ship Hull Block Assembly — Main Production Application

The primary application of a shipyard gantry crane is lifting hull block sections — prefabricated ship hull units weighing 100 to 600 tonnes — from the assembly hall floor or outdoor fabrication area and positioning them on the building berth for welding into the growing hull structure.

Modern shipbuilding uses block construction methodology: the hull is fabricated in sections in a controlled indoor or semi-outdoor environment, then lifted by gantry crane and assembled in sequence on the building berth. The gantry crane makes this production method possible. Without a crane of sufficient capacity and span, blocks must be reduced in size — which increases the number of joints to weld on the berth, slows production, and reduces weld quality control.

A 500T main hoist capacity with 120m span covers the standard building berth of a medium to large shipyard producing vessels in the 10,000–50,000 DWT range. Larger yards building VLCCs, LNG carriers, or large containerships require 800T–3000T capacity and spans up to 170 metres.

Drydock Operations — Ship Repair and Conversion

Shipyard gantry cranes over drydocks support both new construction and ship repair and conversion operations. In repair mode, the crane handles engine removal and replacement, propeller and rudder handling, deck equipment removal, and large structural section replacement.

Drydock cranes also operate in a more confined geometry than building berth cranes. The hook must reach to the drydock floor level — which may be 15–25 metres below quay level — while maintaining clearance above the ship’s superstructure at the upper position. Hook height specification for drydock applications requires careful coordination with the drydock geometry and the vessel profiles to be handled.

Slipway Launch Operations

Shipyards using inclined slipways for vessel launch require gantry cranes that can operate at the slipway gradient and position loads accurately onto the cradle system. Slipway cranes must be designed for the lateral force component that arises from operating on an inclined rail foundation — a load case that does not apply to flat building berth cranes and must be explicitly accounted for in the structural design.

For slipway applications, rail gradient tolerance and the level compensation system for the crane cab and hoist machinery are important specifications. Equipment that relies on gravity-referenced systems — oil lubrication, fluid levels, and some braking systems — must be designed or adapted for the slipway gradient.

Offshore Platform and Module Yard Lifting

Large gantry cranes are also deployed in offshore fabrication yards — assembling oil platform topsides, jacket structures, and living quarter modules. These structures weigh 500 to 2,000 tonnes and require a crane of equivalent or greater capacity to lift and position them during assembly.

The specification profile for an offshore module yard is similar to a shipyard but with some important differences: loads are typically more irregular in shape and weight distribution; the lift plan for each module must be individually engineered; and the yard may need to handle loads that approach or exceed the crane’s standard SWL through engineered tandem lifts using two cranes simultaneously.

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Key Features That Define Our Shipyard Gantry Cranes

AC Variable Frequency Drive on All Motions

All hoist, trolley, and gantry travel drives use AC VFD technology as standard. This provides smooth, stepless speed control from zero to maximum — critical for the precise positioning required when lowering a 300-tonne block section onto a building berth where alignment tolerances are measured in millimetres. Hard stops and speed steps — characteristic of older contactor-controlled drives — are eliminated, reducing mechanical shock and extending the service life of ropes, drums, and structural connections.

Anti-Sway and Precision Positioning System

Load swing on a large shipyard crane — with a hoist height of 50 metres and a heavy block section suspended from a long rigging spread — creates significant positional error at the landing point and imposes dynamic loads on the crane structure. Our standard anti-sway system uses drive motion profiling — the trolley and gantry accelerate and decelerate on a calculated profile that minimizes pendulum swing. For high-precision applications, active anti-sway with laser-based position feedback reduces residual swing at the hook to less than 200mm at full travel speed.

Marine-Grade Corrosion Protection System

Shipyard environments are among the most corrosive industrial settings. Salt-laden air, humidity, and tidal splash zones accelerate coating degradation on exposed structural and mechanical components. Our standard coating system for shipyard gantry cranes specifies:

• Sa 2.5 abrasive blast preparation on all steel surfaces
• Zinc-rich primer (60 microns DFT minimum)
• Epoxy mid-coat (120 microns DFT minimum)
• Polyurethane topcoat (80 microns DFT minimum)
• Stripe coat on all weld seams, edges, and bolt heads

Total minimum DFT of 300 microns. On structures within 50 metres of the waterline or in tidal zones, an additional sacrificial anode system is available for substructure protection.

Safety Systems Standard Package

All shipyard gantry cranes are supplied with a comprehensive safety system as standard:

• Overload protection with automatic cutoff at 110% SWL
• Upper and lower limit switches on all hoists
• End travel limits on trolley and gantry
• Anti-collision system between cranes on the same runway
• Wind speed anemometer with staged alarms and automatic storm securing
• Structural health monitoring (load cycle counter and hoist utilization recorder)
• Emergency stop accessible from ground level, cabin, and maintenance platforms

Classification Society Certification

Shipyard gantry cranes are designed and manufactured to the requirements of major classification societies. Classification is required for cranes operating at classified shipyard facilities and for cranes that will lift marine equipment requiring classification certification. We manufacture to:

• CCS — China Classification Society (standard for Chinese shipyards)
• RS Certificate-Russian Maritime Register of Shipping
• ABS — American Bureau of Shipping
• Bureau Veritas (BV) – common for French-flag and West African trade

The classification surveyor attends factory acceptance testing and issues the crane certificate directly. We coordinate the surveyor schedule as part of our standard project delivery process.

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Trusted across power generation, shipbuilding, metallurgy, and civil engineering, this is the heavy lifting equipment built for projects where performance cannot be compromised.

What Is a Hydraulic Gantry Crane?

A hydraulic gantry crane is a heavy-duty lifting system powered entirely by a hydraulic drive system. It consists of six core components: a gantry frame, lifting mechanism, traveling mechanism, hydraulic power unit, electrical control system, and safety protection devices.

The system raises, positions, and moves extremely heavy loads with stepless speed control and ±1mm synchronization accuracy across multiple lifting points. It operates on standard AC 380V / 50Hz power supply or a self-contained diesel power unit — making it deployable anywhere, with or without grid power.

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Core Technical Specifications

All models are available in custom configurations. Span, lifting height, column stages, and travel mode can be specified to match your exact project requirements.

Product Types

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Key Product Features

Modular, Compact Design

Every component ships in standard containers and assembles on site without heavy auxiliary equipment. The compact footprint fits into tight workspaces where mobile cranes cannot operate. Disassembly is equally fast, keeping project timelines on schedule.

Telescopic Column System

The 2 / 3 / 4-stage telescopic hydraulic columns allow flexible height adjustment to match any lifting requirement. Low-ceiling environments and height-restricted facilities are no obstacle. The collapsed transport height is minimized for easy logistics.

Multi-Mode Travel System

Choose rail-mounted travel for linear corridor operations, or trackless self-propelled travel for open-floor flexibility. A self-propelled chassis upgrade is available for maximum site mobility. Both modes support full load movement without repositioning the load.

±1mm Synchronization Precision

The integrated PLC synchronization module and electro-hydraulic proportional valves maintain all lifting points within ±1mm throughout the entire operation. This level of precision protects sensitive equipment — turbine rotors, transformer cores, precision machinery — from damage during installation.

Wireless Remote Control

A single operator controls the full lifting, traveling, and positioning sequence from a safe distance via wireless remote. Micro-motion control is standard, enabling fine adjustments during critical positioning phases. Wired pendant control is available as an alternative.

Comprehensive Safety System

Every unit is equipped with an overload limiter, travel limit switches, emergency braking, hydraulic safety valves, and a counterbalance valve that holds loads securely at any height — even under hydraulic pressure loss. Safety performance meets international standards including CE and ISO 4301-1.

Application Industries

Power Industry

Generator stators, transformer cores, and gas turbine components. Our hydraulic gantry crane positions equipment weighing hundreds of tons with the precision that sensitive power assets demand.

Metallurgical Industry

Steel billet and slab handling, rolling mill installation and maintenance. Built to operate continuously in demanding steel plant environments under A5–A8 duty classification.

Shipbuilding and Ship Repair

Hull block assembly, main engine installation, dry dock repair operations. Multi-point synchronized lifting keeps blocks aligned during joining — protecting structural integrity from the start of construction.

Civil Engineering and Infrastructure

TBM component assembly, large bridge steel structures, metro station installation. The modular crane deploys in underground stations and alongside existing structures where no other heavy lift solution fits.

Precast Component Manufacturing

PC panel demolding, pipe gallery module handling, large precast concrete stacking and loading. Smooth stepless lifting eliminates the shock loads that damage precast elements during handling.

Port and Logistics

Container handling, heavy cargo loading and unloading, short-distance heavy goods transfer. The crane’s travel mechanism supports load movement without crane relocation, improving handling efficiency.

Tell us your lifting capacity, span, height requirement, and work environment. Our engineering team will recommend the right configuration and provide a detailed technical proposal within 24 hours.

Contact HT Crane today to discuss your project and receive a tailored quotation.

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This page covers everything you need to evaluate a Single Girder RTG Crane: how it works, where it excels, what makes ours different, and the full technical specifications. Ready to specify a unit? Our engineering team responds to enquiries within 24 hours, ensuring you get the right solution for your port or yard.

Product Introduction

The Single Girder Rubber Tired Gantry Crane is a self-propelled, mobile gantry lifting system mounted on rubber tyres. It operates without fixed rails, tracks, or permanent ground infrastructure — making it one of the most flexible solutions available for container handling, industrial yard lifting, and logistics operations where site conditions or operational flexibility make rail-mounted systems impractical.

The crane’s single box girder bridge is supported on two rubber-tyred leg assemblies. The trolley and hoist travel along the bridge to position loads horizontally. The full crane assembly travels longitudinally through the yard on rubber tyres. Multi-mode steering — including crab steering and 90-degree transverse travel — allows precise maneuvering in confined spaces and quick repositioning between rows.

This configuration is particularly well suited to small and medium container depots, precast concrete production yards, steel storage areas, logistics distribution centers, and light port terminal operations where throughput does not justify a full double girder RTG installation.

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Why Buy From Us?

HT Cranes is a professional manufacturer of RTG cranes with over 15 years of lifting experience. Our cranes are exported to ports and logistics yards across Southeast Asia, the Middle East, Africa, and South America. Every unit is factory-tested before shipment and backed by full documentation including CE Declaration of Conformity and ISO 9001 certification records.

We do not resell third-party equipment. Every crane we supply is built, assembled, and tested in-house — giving you full quality traceability from steel fabrication to final commissioning.

Related Case Study

90-Ton Rubber Tyred Gantry Crane Exported to Mexico

Client: Port Logistics Operator | Destination:

Manzanillo, Mexico Capacity: 90t | Span: 8m | Delivered in 14 Weeks

View Full Case Study →

Product Parameters

Main Structure and Components

Bridge Girder

• Single box section steel girder — welded structural steel
• Shot-blast cleaned to Sa 2.5 and multi-layer painted (zinc-rich primer + epoxy + polyurethane topcoat)
• Designed for the full span and rated load at M4–M6 duty classification

Leg Assemblies

• A-frame or portal-type legs, one on each side of the bridge
• Each leg mounted on a rubber-tyre bogie with independent drive motor
• Bogie synchronization control prevents bridge skewing during travel

Rubber Tyre Travel System

• Solid rubber or pneumatic tyres — application-specific selection
• Four-corner bogie layout; all bogies steerable for multi-mode travel
• Suitable for reinforced concrete yard surfaces without crane rail foundations
• Maximum yard grade: 2% loaded (site confirmation required)

Hoisting System

• Wire rope electric hoist or low-headroom hoist (configurable)
• Load-rated hook block with safety latch
• Upper and lower travel limit switches as standard
• Overload protection via load cell — automatic cutout at rated SWL

Electrical System

• PLC-based control with VFD on all motion axes
• IP54 main control panel (IP55 for outdoor environments)
• Emergency stop at all operating positions
• Operational fault diagnostics and hour meter display

Key Features

① No Rail Infrastructure Required

The rubber tyre travel system eliminates crane rails, rail foundations, and the civil engineering work that fixed gantry and rail-mounted systems require. The crane can be operational on a prepared concrete yard surface without structural modification to the ground.

② Multi-Mode Steering for Tight Yards

Straight travel covers primary yard lanes. Crab steering allows diagonal repositioning. 90-degree transverse travel moves the crane sideways between adjacent rows without a wide turning arc. This combination handles the maneuvering requirements of compact container depots and industrial yards.

③ Variable Frequency Drive on All Motions

VFD-controlled travel, hoisting, and trolley traverse provide smooth acceleration and deceleration — reducing mechanical shock on the structure and load, improving positioning precision, and extending drive component service life.

④ Energy-Efficient Drive Options

• Electric (grid-connected): Cable reel or festoon power supply; zero local emissions during operation
• Diesel-electric: Onboard diesel generator powers electric drive motors; suitable for sites without reliable grid supply; regenerative braking reduces fuel consumption during lowering cycles

⑤ Intelligent Anti-Sway Control

Electronic load stabilization detects and corrects spreader or hook swing during travel and placement. Reduces cycle time, improves stack accuracy, and lowers the skill threshold required for consistent operation.

⑥ Robust Corrosion Protection

Multi-layer coating system for outdoor and coastal environments:

• Abrasive blast cleaning: Sa 2.5 standard
• Layer 1: Zinc-rich epoxy primer
• Layer 2: Epoxy intermediate coat
• Layer 3: Polyurethane topcoat
• DFT (dry film thickness): To project specification

Applications

Container Depot and Inland Terminal

Single Girder Rubber Tired Gantry Crane handle 20-foot and 40-foot ISO containers in inland depots, intermodal yards, and small container terminals. Rubber tyre mobility allows repositioning as yard layout and utilization patterns change — without the civil works commitment of a fixed rail system.

Precast Concrete Production Yard

Precast manufacturers use Single Girder Rubber Tired Gantry Crane to lift, move, and stack concrete panels, beams, and bridge elements within open-air production yards. The self-supporting structure eliminates any requirement for a building-mounted runway.

Steel and Metal Fabrication Yard

Outdoor steel storage and fabrication sites use RTG cranes to move steel plate, sections, coils, and fabricated assemblies between storage, processing, and dispatch areas. The rubber tyre system handles imperfect yard surfaces better than rail-mounted alternatives.

Logistics and Distribution Center

General cargo handling facilities use Single Girder Rubber Tired Gantry Cranes for loads exceeding forklift capacity — large machinery components, packaged equipment, oversized palletized cargo, and fabricated assemblies.

Light Port Terminal and Shipyard Ancillary Area

In smaller port facilities and shipyard storage zones where a full double girder RTG is not warranted, a single girder configuration provides practical container and component handling without fixed infrastructure investment.

Maintenance Workshop and Repair Facility

Vehicle maintenance facilities, heavy equipment service workshops, and industrial repair bays use single girder RTG cranes for engine lifts, component positioning, and equipment transfer across large workshop floors.

Comparison: Single Girder vs Double Girder RTG Crane

A single girder configuration is appropriate when lifting capacity, duty cycle, and ground loading all fall within its rated range. For higher capacity, higher throughput port operations, a double girder RTG is the more suitable starting point.

Customization Options

Why Choose HaiTai Crane

Backed by 20+ years of manufacturing experience and exports to 80+ countries, HaiTai Crane delivers CE and ISO 9001:2015 certified lifting solutions to ports, shipyards, and marinas worldwide. From standard configurations to fully engineered custom builds, our technical team tailors every crane to your site conditions and operational requirements.

10+ Years Exp.

5,000+ Customers

50+ Countries

Simon

Crane Solutions Specialist  ·  HT Crane

Specialized in Gantry Crane, Port Crane, Container Crane , Marine Boat Crane & Overhead Crane export solutions. 10+ years helping global clients with pre-sales consultation, capacity selection and site-specific configurations.

+86 136 7352 1295 info@cranehaitai.com Contact Us

This page covers everything procurement teams need: how each MG type differs, what specs apply to your load and environment, and how to match the right configuration to your site conditions. No guesswork. Just practical guidance.

What Is the MG Heavy Duty Trolley Gantry Crane?

The MG gantry crane is a double-beam, trolley-type outdoor crane built for heavy industrial lifting. Its structure uses a box-type welded double beam with π-shaped legs. This design increases torsional rigidity significantly. The crane handles loads from 5 tons up to 500 tons. It runs on ground rails and supports spans from 18 to 40 meters.

Core Engineering Advantages

Unlike single-beam gantry cranes, the MG series uses two parallel main beams. This distributes the load more evenly. The trolley travels between the beams, allowing precise positioning over wide spans. The π-leg design keeps the center of gravity low. That matters when handling asymmetric loads or working near site edges.

The full variable frequency drive (VFD) system adjusts power output automatically based on load. Compared to traditional fixed-speed drives, this reduces energy consumption by 20–30%. Over a 10-year service cycle, that’s a meaningful operating cost difference.

Safety Systems Built In

Every MG heavy duty trolley gantry crane ships with multiple protection layers. These include:

• Sound and light overload alarms
• Anti-top limiters (hoist travel limiters)
• Emergency stop systems
• Imported wire rope rated to ISO standards

The hardened gear reducer and three-in-one transmission system reduce mechanical wear. That means longer service intervals and lower maintenance frequency in demanding environments.

4 MG Gantry Crane Types: Which One Fits Your Operation?

The MG series comes in four structural configurations. Each serves a different use case. Understanding the differences prevents costly over-specification or under-specification.

A-Frame Double Girder Gantry Crane

The A-Frame Double Girder Gantry Crane is a heavy-duty outdoor lifting solution built for large-tonnage operations. Its signature “A”-shaped legs form a wide, triangulated support base. This geometry distributes lateral forces efficiently. The result is a crane that stays stable under wind load, uneven ground conditions, and asymmetric lifts.

The double-girder main beam sits across the top of the A-legs. The electric trolley travels along the full span between beams. This allows precise load positioning anywhere across the working zone. Main and auxiliary hooks can be fitted simultaneously. Dual-trolley configurations support synchronized lifts of long or oddly shaped components.

Structurally, the A-frame variant is the go-to choice when lift weights exceed 50 tons and the site is exposed to outdoor conditions. It meets the rigidity demands of steel mill crane duty while maintaining the span range needed for port berth coverage.

Best for: Steel billet and coil handling in steel mills. Container loading at small-to-mid ports. Wind turbine blade and tower installation. Heavy equipment assembly in nuclear or power plants. Where complex lifts need dual trolleys or main-and-auxiliary hook configurations, the A-frame handles it.

U-Frame Double Beam Trolley Gantry Crane

The U-Frame Double Beam Trolley Gantry Crane takes a different structural approach. Instead of angled A-legs, it uses vertical or near-vertical U-shaped outriggers. The space between the legs is wider and more open. Long materials — steel plates, vehicle frames, pre-cut profiles — can pass under the crane body without obstruction.

This clearance is the defining advantage of the U-frame design. In automotive plants, it allows full vehicle frames to move laterally through the crane’s working zone. In metal processing facilities, steel sheets up to several meters in length travel freely beneath the structure. This removes the need for secondary repositioning equipment.

The double-beam construction gives the U-frame solid rigidity for loads up to 50 tons. It handles impact loads well. Dusty, humid, and high-vibration factory environments do not degrade its structural performance over time. The U-frame suits indoor and semi-indoor sites where medium tonnage and material geometry are both key selection factors.

Best for: Machine part handling in heavy machinery factories. Vehicle frame transport in automotive plants. Cross-zone warehouse movement. New energy battery component logistics. The U-frame resists impact well and performs reliably in dusty or humid environments.

MG Box Type Double Beam Gantry Crane

The MG Box Type Double Beam Gantry Crane is the highest-capacity variant in the MG series. It handles loads from 5 tons up to 500 tons. The main beams are fabricated from thick steel plates welded into a closed box cross-section. This profile achieves maximum bending and torsional stiffness for a given beam weight.

The box beam’s rigid geometry is critical for high-tonnage precision work. When a 300-ton load hangs mid-span, beam deflection must remain within tight tolerances. The box structure keeps deflection predictable and within ISO 22986 crane stiffness standards. That matters in applications like prefabricated bridge beam placement, where millimeter-level accuracy affects structural alignment.

The outriggers connect rigidly to the main beams — not with pins or bolted flanges, but through full-penetration welds. This lowers the whole-machine center of gravity. The crane resists overturning moments even under eccentric loads. For the most demanding industrial lifting environments — metallurgical plants, heavy machinery assembly halls, and large logistics centers — the Box type delivers the structural performance that lighter configurations cannot match. Double hooks are available for complex lift sequences.

Best for: Iron and steel metallurgy. Metal processing plants. Heavy machinery manufacturing and assembly lines. Large-scale warehouse and 3D logistics facilities. When tonnage is high and precision matters, the Box type is the standard choice. Double hooks are available on request.

MG Truss Type Double Girder Gantry Crane

The MG Truss Type Double Girder Gantry Crane replaces solid box beams with an open lattice truss structure. Steel members are arranged in triangulated patterns between top and bottom chords. This achieves high structural strength with significantly less material. Dead weight drops. Wind resistance decreases. Transport volume reduces.

For outdoor sites in coastal, high-altitude, or open-plain environments, wind load is a primary engineering concern. A solid box beam acts like a sail — it catches wind across its full surface area. A truss beam lets wind pass through the lattice with minimal resistance. This fundamental difference makes the Truss type the safer structural choice for exposed locations where wind speeds regularly exceed 10 m/s.

The lighter self-weight also reduces foundation and rail requirements. Ground bearing pressure drops. Civil construction costs on site go down. For remote infrastructure projects — hydropower stations, railway freight depots, or coastal port auxiliary operations — where logistics and site preparation budgets are constrained, the Truss type offers an economically sound solution without sacrificing lifting performance. Anti-corrosion treatment on all truss members extends service life in marine and chemical-adjacent environments.

Best for: Hydropower station gate operations. Railway freight yard container and rail handling. Port auxiliary lifts for non-containerized heavy parts. Open-air sites in high-wind regions. Corrosion resistance makes the Truss type suitable for coastal and marine-adjacent environments.

Type Comparison at a Glance

Where MG Gantry Cranes Operate

Port and Rail Freight Applications

The MG crane’s large span and double-cantilever structure allow efficient container handling across multiple lanes. With outreach of up to 7.5 meters, it covers wide berths without repositioning. Port operations in Brazil, Egypt, Malaysia, and Indonesia have deployed MG-series cranes for large-scale infrastructure projects.

Mining, Metallurgy, and Heavy Industry

The MG series runs stably in temperatures from –25°C to +40°C. It works with grab buckets, electromagnetic hoists, and other attachments. That makes it suitable for continuous handling of ore, steel billets, and bulk industrial materials in extreme conditions. Explosion-proof variants are available for sensitive environments on request.

Infrastructure and Manufacturing

Prefabricated beam installation requires both high lift height and precise positioning. The MG Box type handles this with its low-speed lifting range (0.1 m/min) and intelligent control systems. In large factories, the same crane moves oversized assemblies between production zones with minimal manual intervention.

Modular Design: What It Means for Your Procurement

The MG crane’s main beams and legs connect via high-strength bolts. This modular approach has direct procurement benefits. Components ship in standard containers. On-site assembly requires fewer specialized tools. Lead time for installation shortens compared to fully-welded rigid frames.

For remote sites or projects with limited access roads, this matters. A 500-ton Box type can arrive in sections and be assembled on location without heavy transport permits for oversized loads. Ask your supplier to confirm which sections require special handling before finalizing logistics planning.

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Control Options and Adaptability

The MG crane supports three control modes simultaneously:

Power feed options include conductive cable drums or enclosed busbar systems. Busbar systems reduce cable wear in high-cycle environments. For outdoor rail yards, sealed cable drums perform better in wet conditions.

Summary

The MG Heavy Duty Trolley Gantry Crane is a well-engineered solution for operations that demand reliability, adaptability, and load capacity above what light-duty cranes can handle. The four type variants — A-frame, U-frame, Box, and Truss — cover most heavy industrial use cases from 50-ton outdoor port work to 500-ton indoor steel mill applications.

Before requesting a quote, prepare the following details:

1. Maximum required lifting capacity (tons)
2. Required span between rails (meters)
3. Required lifting height (meters)
4. Site environment (indoor/outdoor, temperature range, dust/humidity)
5. Intended load type (containers, billets, bulk material, prefab beams)
6. Preferred control mode

With these inputs, an engineer can confirm the right type, work duty class (A5 standard or higher for intensive cycles), and specify the trolley configuration. Custom spans, double hooks, and explosion-proof ratings are available on all four types.

10+ Years Exp.

5,000+ Customers

50+ Countries

Simon

Crane Solutions Specialist  ·  HT Crane

Specialized in Gantry Crane, Port Crane, Container Crane , Marine Boat Crane & Overhead Crane export solutions. 10+ years helping global clients with pre-sales consultation, capacity selection and site-specific configurations.

+86 136 7352 1295 info@cranehaitai.com Contact Us

Buyers often reach the double girder decision after outgrowing a lighter crane or after realizing that a single girder model cannot meet their hook height or span requirements. The challenge then becomes specification: double girder cranes involve more variables, more civil infrastructure, and larger capital commitment than their lighter counterparts.

This page walks you through what defines a double girder gantry crane, what to specify, where it fits, and how to evaluate a supplier for a purchase of this significance.

What Is a Double Girder Gantry Crane?

A double girder gantry crane uses two parallel horizontal girders — the main beams — supported at each end by leg structures that run on ground-level rails. The crane trolley, which carries the hoist, travels on rails mounted on top of the two girders. This top-running trolley arrangement is the defining structural feature that distinguishes a double girder from a single girder crane.

The top-running configuration provides two critical advantages: higher hook height for the same overall crane height, and the ability to carry much heavier loads over much larger spans. For heavy industrial applications, these two advantages are often non-negotiable requirements — which is why double girder gantry cranes dominate the heavy end of the market.

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How It Compares to Single Girder

The clearest decision rule: if your SWL requirement is above 20 tonnes, or if your span exceeds 30 metres, a double girder design is almost certainly the correct structural choice. Below those thresholds, evaluate whether a single girder meets your hook height and duty cycle needs before committing to the higher capital cost.

Box Girder vs Truss Girder Construction

Double girder gantry cranes are built using one of two girder types:

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Product Specifications

Capacity and Span Overview

Core Technical Parameters

Hoist and Trolley Configuration

The hoist-trolley assembly on a double girder crane is a more substantial unit than the hoist on a single girder design. Three configurations are commonly specified:

Standard electric wire rope hoist trolley — the most common configuration for 10T–80T. A wire rope hoist is integrated into a four-wheel trolley that runs directly on the girder rails. This is the simplest and most maintainable arrangement.

Separate crab trolley (crane trolley) — used on heavy and extra-heavy cranes above 80T. The crab consists of a fabricated trolley frame carrying a dedicated hoist mechanism with drum, motor, gearbox, and brake system. This configuration handles the highest loads and duty cycles and is fully serviceable in the field.

Twin hoist configuration — two hoists on a single trolley or two independent trolleys on the same crane. Used when tandem lifts are required — lifting one end of a long, heavy object with each hoist simultaneously. Common in shipyards and structural steel fabrication.

Application Scenarios

Shipbuilding and Ship Repair Yards

Shipyards represent the most demanding double girder gantry crane environment. Cranes in this sector routinely operate at high duty cycles, handle loads close to their rated SWL, and work in a salt-air environment that accelerates corrosion. Spans of 40–60 metres are common to cover the full width of a ship block assembly area or drydock entrance.

For shipyard applications, the crane duty class is typically M6 or M7 per ISO 4301, reflecting the high lift frequency. Structural design includes additional corrosion protection, and maintenance access provisions — walkways, service platforms, and lifting points for hoist servicing — are built into the design from the outset. This is not a standard workshop crane scaled up. It is a specifically engineered machine for one of the most demanding industrial environments.

Steel Mills and Heavy Metal Processing

Steel service centers and rolling mill facilities use double girder gantry cranes for coil handling, slab transfer, and mold transportation. The defining characteristic of this application is thermal environment: cranes operating above areas where molten metal is processed must be specified for elevated ambient temperatures, with heat shields on structural and electrical components.

Coil handling cranes typically use C-hook attachments rather than a standard wire rope hook — a C-hook engages the coil’s inner bore and holds it during horizontal movement without requiring a sling. This is a specialized attachment that must be specified and load-rated as part of the original crane procurement, not added as an afterthought.

Precast Concrete Manufacturing

Precast concrete factories use large-span double girder gantry cranes to lift form molds, move cured elements through the production line, and load finished products for transport. Precast elements — wall panels, floor slabs, bridge beams — are heavy, often irregular in shape, and require precise placement.

Cranes in precast applications are typically 20T–80T with spans of 20–35 metres, operating at moderate duty cycles (M4–M5). The key specification requirements are accurate load positioning and reliable anti-sway control — a swinging concrete panel in a production line is a safety hazard and causes production disruption.

Heavy Logistics, Module Yards, and Offshore Fabrication

Module yards for oil and gas construction, wind turbine assembly facilities, and heavy logistics hubs all share a similar profile: large open areas, heavy and irregular loads, and the need for the crane to work across the full yard width. Double girder gantry cranes in these environments are typically 50T–320T with spans matching the yard width — often 30–60 metres.

For outdoor module yard applications, the crane must be designed for the site’s wind load zone, with storm anchoring systems and wind speed monitoring as standard. Structural corrosion protection must be appropriate for the coastal or industrial environment.

Key Features That Define Our Double Girder Cranes

Full AC VFD Drive on All Axes

All hoist, trolley, and gantry travel motions use AC variable frequency drives as standard. This provides smooth, stepless speed control across the full operating range — from slow precision positioning to full travel speed. VFD drives also extend the service life of mechanical components by eliminating the shock loads that older contactor-controlled systems imposed on drive trains.

Energy regeneration on the hoist axis — feeding recovered braking energy back to the power supply — is standard on all cranes above 32T. In high-throughput operations with frequent long lowering cycles, regenerated energy meaningfully reduces operating cost over the crane’s service life.

Anti-Sway Control

Load swing is a safety and productivity issue on large-span, high-lift cranes. Our standard anti-sway system uses motion profile control — the drive system accelerates and decelerates the trolley according to a calculated profile that minimizes pendulum swing at the hook. For cranes handling precision loads or operating in restricted clearance environments, active anti-sway with encoder feedback is available as an upgrade.

Structural Design and Weld Quality

HT crane double girder gantry crane structures are designed to EN 13001 and FEM 1.001 standards. All primary structural welds are full-penetration welds completed by certified welders (EN ISO 9606-1). Non-destructive testing — ultrasonic or magnetic particle inspection — is performed on all critical joints as a standard manufacturing step, not an optional add-on.

Box girder camber is pre-set during fabrication to compensate for the deflection under full rated load, ensuring the girder remains level in service. Buyers should ask any supplier to confirm how camber is calculated and verified — it is a basic quality indicator that separates serious manufacturers from assemblers buying standard sections.

Corrosion Protection for Industrial Environments

Our standard coating system for double girder gantry cranes specifies Sa 2.5 abrasive blast preparation followed by a zinc-rich primer, epoxy mid-coat, and polyurethane topcoat — total dry film thickness of 280–320 microns. For shipyard and coastal environments, an additional stripe coat on weld seams and exposed edges is applied as standard. Hot-dip galvanizing is available for specific structural components in highly corrosive environments.

Civil Infrastructure: What You Need Before the Crane Arrives

Rail Foundation Design

A double girder gantry crane imposes significant wheel loads on its rail system. The maximum wheel load — which determines the foundation design — depends on the crane’s self-weight, maximum SWL, and the number of wheels per bogie. We provide full wheel load documentation as part of our pre-contract technical package.

Rail foundation design is a geotechnical and structural engineering task. The foundation must carry the wheel loads through the operating cycle and seasonal ground movement without differential settlement that would cause the crane to rack on its rails. Engage a qualified civil engineer with crane foundation experience before finalizing your site design — do not rely on the crane supplier to size the foundation.

Electrical Supply Requirements

Double girder gantry cranes in the heavy and extra-heavy categories have peak power demands of 200 kW to over 1,000 kW depending on capacity and speed. The electrical supply infrastructure — transformer, distribution board, conductor rail or festoon system — must be sized for the crane’s peak demand, not average demand. We provide detailed electrical supply specifications for each project.

Supplier Evaluation: What Matters at This Scale

At the scale of a double girder gantry crane purchase, supplier evaluation is as important as equipment specification. Four areas require particular attention:

Structural engineering credentials — does the supplier have in-house structural engineers, or do they rely on bought-in design services? Ask for the structural design standard applied and the method of verifying compliance. EN 13001 compliance should be verifiable, not self-declared.

Welding certification — all primary structural welders should hold current EN ISO 9606-1 certification. Ask for the welder qualification records as part of the quality documentation package.

Load test protocol — factory acceptance testing to 110% SWL is the minimum standard. For cranes above 100T, witnessed testing by an independent inspection body is strongly recommended. Confirm who witnesses the test and what certificate is issued.

Reference installations — request contact details for at least two operating customers with cranes of similar capacity and application. Visit if possible. A supplier with no verifiable operating references at this scale is a risk regardless of their quoted price.

A double girder gantry crane is a major capital investment with a service life of 20–25 years. Getting the specification right, choosing a supplier with genuine engineering capability, and ensuring the civil infrastructure is properly designed are the three things that most directly determine whether that investment pays off.

The specification process requires more upfront work than lighter crane categories — but the decisions made at specification stage are largely irreversible once manufacturing begins. Invest the time to define your load case, duty cycle, environmental conditions, and hook height requirements precisely before approaching any supplier.

HT crane team provides full pre-contract technical support at no cost: load case review, span and hook height confirmation, duty class calculation, and civil infrastructure guidance. Contact us with your project details and we will provide a complete technical proposal.

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This page breaks down all four single girder gantry crane types available from haitai Crane. You will find full specifications, clear application guidance, a direct type comparison, and a pre-order checklist. No unnecessary complexity. Just the information procurement teams need to make a confident decision.

What Is a Single Girder Gantry Crane?

A single girder gantry crane uses one main beam supported by two legs that travel along ground rails. An electric hoist runs along the underside of the beam. This design is simpler and lighter than double-girder configurations. It costs less to build, install, and maintain.

Key Structural Components

Every single girder gantry crane shares the same core structure:

• Main beam — carries the hoist rail and handles the full bending load
• End beams — connect the main beam to the legs and mount the travel drive
• Legs — support the entire structure and transfer loads to the rail
• Ground beams — connect and stabilize the outriggers at track level
• Electric hoist — provides vertical lift and horizontal travel along the beam
• Cab or pendant control — operator interface for safe, precise positioning

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4 Types of Single Girder Gantry Crane: Full Specifications

Haitai crane offers four distinct single girder configurations. Each addresses a different combination of load weight, span, environment, and structural need.

Type 1 — MH Box Type Single Girder Gantry Crane

Product Overview

The MH Box type uses a closed rectangular steel box section as the main beam. Steel plates are welded together to form this profile. The result is a beam with high bending stiffness and strong torsional resistance. This matters when the hoist carries loads close to the rated capacity over long spans.

Box beams maintain consistent deflection behavior across the full span range. In high-temperature environments — steel plants, foundries, or facilities near heat-generating processes — the box section retains structural integrity better than open-truss alternatives. Its sealed profile also resists dust ingress, which reduces long-term wear on internal surfaces.

This is the most structurally capable variant in the single girder range. It suits high-load, long-span applications where structural margin and safety reliability are the primary selection criteria.

Application: Manufacturing plants, steel facilities, logistics and warehouses, power and energy industry where load capacity and operational safety requirements are high.

Key Features: High load capacity, strong structural rigidity, resistance to high-temperature environments, strong anti-bending and anti-torsion performance. Suitable for large lifting weights and wide-span operations.

Type 2 — MH Truss Single Beam Gantry Crane

Product Overview

The MH Truss type replaces the solid box beam with a steel tube lattice truss structure. Members are arranged in triangulated patterns, creating a strong frame with significantly less material and lower self-weight. This reduces the load transferred to the ground rails and lowers foundation requirements.

The open truss profile offers natural wind resistance. Wind passes through the lattice rather than pushing against a solid surface. For outdoor sites or open-sided facilities exposed to prevailing winds, this structural behavior is a meaningful safety advantage. Corrosion protection is applied to all truss members to extend service life in humid or coastal environments.

The truss type also travels across the widest span range in the single girder lineup — up to 31.5 meters. For yards handling bundled steel, prefabricated concrete panels, or large engineering components, this combination of span and low dead weight makes the truss type a practical and cost-efficient choice.

Application: Construction sites, warehousing, machinery manufacturing, ports and harbor operations. Common loads include steel plates, structural profiles, large components, containers, bundled goods, prefabricated panels, and general engineering materials.

Key Features: Steel tube truss main structure, lightweight design, strong wind resistance, large operating range, good visual aesthetics for client-facing facilities.

Type 3 — L-Type Single Beam Hoist Gantry Crane

Product Overview

The L-type single beam gantry crane uses an asymmetric leg configuration. One leg is taller and vertical. The other is shorter and angled, forming an “L”-shaped profile when viewed from the side. This geometry creates a wide, stable footprint without requiring equal-height legs on both sides.

The asymmetric leg design is particularly effective where one side of the crane’s working zone is constrained — near a wall, an existing structure, or a road edge. The shorter L-leg can sit closer to an obstacle while the taller leg maintains full working clearance on the open side. This makes the L-type useful in logistics yards where trucks load and unload from one side only.

High-performance electric hoists provide precise vertical positioning. The crane travel speed of 20–40 m/min supports efficient throughput in active loading zones. It handles loads from 5 to 10 tons across spans of 16 to 30 meters — well suited for truck loading bays and railway wagon operations.

Application: Construction, logistics, manufacturing, and steel facilities. Typical tasks include lifting raw materials, semi-finished goods, bricks, steel bars, and construction materials; loading and unloading from trucks and railway wagons.

Key Features: L-shaped frame provides strong stability and high space utilization. High-performance electric hoists enable accurate positioning and efficient goods handling.

Type 4 — BMH Single Girder Semi Gantry Crane

Product Overview

The BMH Semi Gantry Crane is a hybrid structure. One side of the crane runs on a ground rail like a standard gantry crane. The other side runs on an elevated runway rail mounted to an existing wall or column. This removes the need for a second freestanding leg entirely.

The semi-gantry configuration maximizes floor space utilization. In workshop production lines where every meter of floor width contributes to throughput, eliminating one ground rail and its supporting structure creates usable working area. Civil construction costs drop compared to full gantry installations. Installation time is shorter.

The BMH Semi is rated at A4 work duty class — appropriate for light-to- moderate use cycles, typically in single-shift operations. It handles loads from 2 to 16 tons and suits facilities processing molds, glass, prefabricated panels, agricultural materials, and light manufacturing components. Anti-corrosion and anti-dust custom coatings are available for food-adjacent or chemical environments.

Application: Small and medium warehousing, logistics facilities, workshop production lines, light industry, automobile manufacturing, and agricultural operations. Typical loads include molds, raw materials, stone, glass, prefabricated concrete panels, and construction materials.

Key Features: High space utilization, low maintenance cost, high positioning accuracy. Customizable anti-corrosion and anti-dust protection. Ideal for facilities with existing wall or column runway infrastructure.

Type Comparison at a Glance

Where Single Girder Gantry Cranes Operate

Logistics Centers and Warehouses

The single girder gantry crane handles pallet loads, bundled goods, and general freight efficiently. Spans of 7.5–35 meters cover most warehouse bay widths. The MH Box type suits high-cycle, high-capacity zones. The BMH Semi suits space-constrained workshop areas where ground rail count must be minimized.

Construction Sites and Precast Yards

Prefabricated beams, concrete panels, and structural steel all require reliable outdoor crane coverage. The MH Truss type performs well here. Its wind-resistant structure and lifting height up to 24 meters make it the preferred choice for open-air precast operations. Sites in coastal or high-wind regions benefit from the truss profile’s reduced wind load exposure.

Manufacturing and Steel Plants

Steel plants require cranes that tolerate heat, dust, and high-frequency use. The MH Box type is rated for these conditions. Its anti-bending and anti-torsion performance handles asymmetric loads common in coil and billet handling. At A5 duty class, it supports two-shift operations with regular loads near rated capacity.

Ports and Railway Freight Operations

For truck and wagon loading bays, the L-type crane provides efficient coverage at spans of 16–30 meters. Its asymmetric leg layout works with the uneven access patterns typical of logistics terminals. The MH Truss type handles container and bulk material work where wider spans and outdoor exposure are both factors.

Customization Options

Standard configurations cover most applications. When site conditions fall outside standard ranges, Haitai Crane offers full custom engineering:

• Lifting Capacity: 2–32 ton (standard); extended on request
• Span: 5–35 m, adjustable to fit actual rail spacing
• Lifting Height: 6–24 m, configurable to match facility dimensions
• Lifting Speed: 0.8–8 m/min, adjustable for precision or throughput
• Control Options: Pendant control / wireless remote / operator cabin
• Special Coatings: Anti-corrosion, anti-dust, food-grade finish

Custom orders require a full site specification. Lead time is longer than standard configurations. Submit requirements early in the procurement cycle to avoid project delays.

Summary and Next Steps

The single girder gantry crane covers the 2–32 ton working range across logistics, manufacturing, construction, and port environments. The four available types — MH Box, MH Truss, L-type, and BMH Semi — address different structural, environmental, and operational needs. No single type fits every site. The right choice depends on your actual span, lift height, load frequency, and facility layout.

Haitai Crane has supplied gantry crane solutions to infrastructure and industrial projects across Brazil, Pakistan, Indonesia, Malaysia, Egypt, and other markets. Each unit ships with 100% pre-delivery load and safety testing. Warranty coverage runs 3–5 years with 24/7 online support and on-site assistance available when needed.

10+ Years Exp.

5,000+ Customers

50+ Countries

Simon

Crane Solutions Specialist  ·  HT Crane

Specialized in Gantry Crane, Port Crane, Container Crane , Marine Boat Crane & Overhead Crane export solutions. 10+ years helping global clients with pre-sales consultation, capacity selection and site-specific configurations.

+86 136 7352 1295 info@cranehaitai.com Contact Us

The semi gantry crane uses one leg on the ground and one side supported by an existing building column or runway rail on the wall. This hybrid design reduces the crane’s footprint, eliminates one set of floor rail foundations, and integrates with the building structure in a way that a full gantry crane cannot. The result is maximum coverage in minimum space — at a lower civil works cost than either alternative.

What Is a Semi Gantry Crane?

The Defining Structure

A semi gantry crane — also called a half gantry crane — has an asymmetric support structure. One end of the main girder rests on a standard leg that runs on a ground-level rail. The other end is supported by a trolley or bracket that runs on a runway rail attached to an existing building column, wall structure, or dedicated runway beam.

This means the crane covers the full span between the building column and the ground rail, without needing a second set of legs and without the full rail system that a standard gantry crane requires on both sides. The single leg travels on one ground rail. The other rail is elevated — mounted to the building structure at the required height.

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Why This Configuration Exists

The semi gantry crane design emerged from a practical operational need: facilities where one side of the working area is bounded by a building wall or column line, and full floor coverage is required without the footprint of two independent rail systems.

Typical examples: a machine shop where equipment lines one wall and the crane must serve the full floor area; a loading bay where one wall is the building structure and the other side is open to a yard; a prefabrication area where columns on one side are structural and cannot be moved, but floor space on the other side is unobstructed.

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Single Girder Semi Gantry vs Double Girder Semi Gantry

Semi gantry cranes are available in both single and double girder configurations, following the same logic as standard gantry cranes:

For the majority of semi gantry crane applications — workshop lifting from 3T to 16T — the single girder configuration is the appropriate and cost-effective choice. Double girder semi gantry cranes are used when hook height or heavy load requirements push beyond single girder limits.

Product Specifications

Standard Parameters

Structural Configuration Options

Three structural variants cover the full application range:

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Application Scenarios

Manufacturing Workshops With Existing Building Columns

This is the most common semi gantry crane application. The facility already has structural columns along one wall — either from the building’s original design or from a previous installation. Installing an overhead crane would require significant structural reinforcement. A full gantry crane would need rails on both sides and would occupy floor space that is currently used for equipment or workflow.

The semi gantry crane solution: a ground rail runs along the open side of the workshop floor. The existing building column carries a runway beam at the required height. The crane covers the full workshop width from column to ground rail, using the building’s own structure on one side and a minimal floor rail on the other. Civil works are reduced to one rail foundation instead of two. The building structure carries one side of the crane load — exactly what it was designed to do.

Loading Bays and Dispatch Areas

Facilities with covered loading bays — where one side is the building wall and the other side is open to a yard or loading apron — benefit directly from the semi gantry configuration. The covered side uses the building structure for the elevated rail. The open side uses a single ground rail with a standard leg.

This arrangement allows the crane to serve both the indoor storage area and the outdoor loading apron with one crane. No full gantry crane could achieve this without encroaching on the loading apron with a second set of legs. No jib crane covers enough area. The semi gantry is the natural solution.

Steel and Metal Fabrication Shops

Fabrication shops handling material up to 20T — structural steel, plate, piping, and assemblies — frequently operate in buildings where overhead cranes are impractical due to roof structure limitations and where a full gantry crane would create floor congestion. The semi gantry crane provides the lifting capacity needed without either constraint.

For this application, a 10T–16T single girder semi gantry with a span of 12–20 metres is typical. The semi gantry crane handles raw material receiving, in-process assembly moves, and finished product loading — the full production cycle — without forklift interference on the workshop floor.

Maintenance and Overhaul Facilities

Equipment maintenance bays — for large vehicles, power generation equipment, and industrial plant — often have one fixed wall structure and require lifting access across the full bay width. The semi gantry crane fits this geometry precisely: the wall carries one rail, the floor carries the other, and the full bay is covered with one crane and one operator.

For maintenance applications, the duty cycle is typically low — M3 or M4 — which means the crane is designed for moderate lift frequency rather than continuous production use. This affects the structural specification and the hoist duty rating. Always confirm the duty class with your supplier rather than defaulting to the heaviest available option.

Key Specification Considerations for Buyers

Building Structure Assessment Is Non-Negotiable

Before ordering a semi gantry crane, the building column or wall structure that will carry the elevated runway rail must be assessed by a structural engineer. The crane imposes dynamic loads on the building structure — not just the static weight of the crane and its load, but the accelerating and braking forces from gantry travel and hoist motion.

Many buyers assume that because the column is there, it can carry a crane. This assumption is frequently wrong. The original building design may not have included crane loads. The column section, connection details, and foundation may be adequate — or they may not be. This is not a risk worth taking. A structural assessment before procurement protects you from discovering the problem after the crane is installed.

HT crane provide a crane reaction load document — specifying the forces the crane imposes on the building structure — as part of our standard pre-contract technical package. Provide this to your structural engineer alongside the building drawings for the assessment.

Span and Hook Height: Confirm Both Against Your Layout

The crane’s span is the distance between the centreline of the ground rail and the centreline of the elevated runway rail. This is not the same as the width of the working area — the leg and the building bracket each consume some of the span. Measure the actual working width you need to cover, then confirm the crane span required to achieve it.

Hook height is limited by the height of the elevated runway rail and the headroom available between the rail and the building structure above it. In buildings with limited clearance, this is frequently the binding constraint. Measure carefully and provide actual dimensions — not estimates — to your supplier.

Duty Class: Match to Actual Use

Duty class determines how the crane structure and hoist are designed for fatigue life. Specifying a higher duty class than your operation requires adds unnecessary cost. Specifying too low creates a crane that reaches the end of its structural fatigue life before its expected service life — a failure mode that is not always visible until damage is already significant.

Estimate your average daily lifts, the typical load as a percentage of maximum SWL, and your intended crane service life in years. Provide these figures to your supplier and ask them to confirm the correct duty class per ISO 4301 or FEM 1.001. This is a basic application engineering step — any credible crane manufacturer will do it as a matter of standard process.

Why Buyers Choose Direct Manufacturer Supply

A semi gantry crane is a custom-engineered product. Every installation has a unique combination of span, height, building structure type, and operational requirement. A trading company cannot engineer this — they pass the specification to a manufacturer and mark up the result. You lose direct access to the engineers, you lose cost transparency, and you gain a layer of delay when technical questions arise during manufacturing or installation.

Buying direct means your specification goes to the engineers who will build the crane. Questions are answered by the people who designed it. Changes are implemented without intermediary delays. Documentation — CE certificate, load test report, structural drawings — comes directly from the manufacturing entity.

A semi gantry crane is the right solution when a full gantry crane creates too large a footprint, an overhead crane requires building upgrades that are not justified, and a jib crane does not cover enough area. It uses your building structure as one support, reduces civil works to a single ground rail, and delivers full working area coverage in a configuration that fits the geometry of the facility you actually have.

The specification process requires a structural assessment of your building and careful measurement of span and hook height. Both steps are straightforward with the right information — and we provide the crane reaction load data you need to make them simple.

Contact our engineering team with your span, load, hook height, and building structure details. We will provide a complete technical proposal and the structural load documentation your building engineer needs for the assessment.

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