Double Girder Rail Mounted Gantry Crane

A Double Girder Rail Mounted Gantry Crane is a type of gantry crane that travels on rails laid on the ground and features two main girders across the span. These cranes are often used for handling large and heavy loads such as containers, steel coils, large machinery, and structural components. Due to their rail-mounted nature, they are very stable and suitable for long span and high-capacity operations.

Core Components：Engine, Bearing, Gearbox, Motor, Gear

Place of Origin：Henan, China

Warranty：2 years

Weight (KG)：50000 kg

Video outgoing-inspection：Provided

Machinery Test Report：Provided

Application：Outdoor

Keywords：Gantry Crane

Rated Loading Capacity：50Ton

Cross travelling speed：44.6m/min

Long travelling speed：47.1m/min

Control way：cabin

Power supply：Cable reel

Steel track：QU80

Power：3-phase AC 50HZ 380V

1.Main beam

Structure & Design
1)Double Box Girder Construction:
The crane uses two parallel box-type girders, providing exceptional bending resistance and torsional rigidity. This structure is ideal for high-capacity and wide-span lifting tasks.
2)Material:
Made from high-strength Q235B or Q345B carbon steel (or equivalent), ensuring durability, fatigue resistance, and long service life.2)
3)Welding Process:
Full-penetration, automated submerged arc welding (SAW) for seamless joints.
Weld seams undergo non-destructive testing (NDT) such as ultrasonic or magnetic particle inspection to ensure structural integrity.
4)Reinforcement Plates & Ribs:
Internal stiffeners are added to enhance load distribution and reduce deformation under heavy weight.
External ribs at joint locations to improve fatigue resistance.

2.Lifting System

1)Electric Hoist or Winch
Type: Heavy-duty electric wire rope hoist or winch.
Design: Mounted on a trolley frame for horizontal movement across the girders.
Capacity: Common ranges from 10 tons to 200+ tons, depending on crane specification.
Structure: Includes motor, gearbox, drum, and wire rope.
2)Motor & Gearbox
Motor: High-efficiency electric motor, often three-phase asynchronous motor.
Insulation class: F or H; protection class: IP54/IP55.
Gearbox: Helical or planetary type with hardened gear surface for long lifespan and low noise.
3)Wire Rope & Drum
Wire Rope: High-strength, anti-twist steel wire rope.
Drum: Grooved steel drum to guide the rope evenly and reduce wear.
Safety: Equipped with rope guide and pressure roller.
4)Hook Block
Material: Forged carbon steel with swivel capability.
Design: Single or double pulley block depending on load.
Latch: Spring-loaded safety latch to prevent load slippage.
5)Braking System
Electromagnetic or hydraulic brakes integrated into the hoist motor.
Automatically activates during power failure or emergency stop.
6)Limit Switches
Upper and lower limit switches to prevent over-hoisting or over-lowering.
Can be mechanical, magnetic, or proximity-type.
7)Overload Protection Device
Monitors hoisting load and prevents operation when exceeding rated capacity.
Often integrated into the PLC control system or load cell.

3.End carriage

Structure and Design
1)Robust Welded Construction
Made of rectangular steel tubes or reinforced plates, welded and stress-relieved to ensure strength and dimensional accuracy.
2)Integration with Wheels and Drive System
Houses the wheel sets, crane traveling motors, gears, and brakes to move the crane horizontally along the rails.
3)Connection with Main Girders
The main girders are either bolted or welded to the end carriages. Precision machining ensures seamless alignment for trolley movement and structural integrity.

4.Crane travelling mechanism

1)Smooth & Stable Movement
High-precision gearboxes and motor control reduce vibration and enhance safety.
2)Anti-Skewing Control
Ensures both sides of the crane move in perfect alignment-critical for long-span cranes.
3)High Safety Standards
Travel limit switches, emergency brakes, and overload protection built-in.
4)Weather Resistance
For outdoor use, mechanisms are sealed and IP-rated to withstand rain, dust, and heat.

5.Trolley travelling mechanism

Key Features & Advantages
High Precision: Allows exact positioning of the load across the entire span.
Low Noise & Smooth Operation: Thanks to gear reducers and motor soft-start systems.
Durable Components: Designed for long service life under continuous or heavy-duty use.
Low Maintenance: Enclosed gears and sealed bearings protect from dust and moisture.

6.Crane wheel

1)Forged Steel Core
Ensures high load-bearing capacity and impact resistance under dynamic loads.
2)Heat Treatment
Increases surface hardness while maintaining core ductility-ideal for long-term rail use.
3)Precision Machining
The tread and flange are machined for true running and minimal vibration.
4)Self-lubricating Bearings (Optional)
Used in modern designs to reduce maintenance and wear.

7.Crane Hook

Structural Details
1)Shank & Nut Design
The hook is fixed to the hook block via a threaded shank, nut, or bearing-mounted swivel system.
2)Thrust Bearing Assembly
Allows the hook to rotate under load without twisting the wire rope.
3)Latch Mechanism
Equipped with a spring-loaded safety latch to prevent accidental load release.
4)Hook Block (Pulley Group)
The hook is part of the hook block, which includes sheaves, bearings, and rope guide rollers.

8.Motor

Key Features
1)High Starting Torque – Required for lifting heavy loads or starting under full load.
2)Smooth Acceleration & Deceleration – Especially with VFDs, to reduce mechanical stress and load swing.
3)Compact Design – Space-saving structure suitable for overhead or gantry crane applications.
4)Integrated Brakes – Electromagnetic brakes are often combined with the motor for precise and safe stopping.

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9.Sound and light alarm system & limit switch

1)Sound and Light Alarm System
Purpose:
Warn nearby workers before and during crane operation.
Indicate crane startup, movement, overloading, emergency, or malfunction.
Comply with industrial and safety regulations.
2)Limit Switches
Purpose:
Define the maximum allowable travel distance for trolley, hook, or crane.
Prevent overtravel, overlifting, or collision with end stops or structures.

10.Safety Devices

1)Overload Protection (Load Limiters)
Purpose: Prevents lifting loads that exceed the crane's rated capacity, avoiding strain and potential failure of structural components.
Operation: A sensor or load cell monitors the load on the hook. If the weight exceeds the limit, the crane's control system triggers an alarm or automatically stops the hoisting operation.
Type: Electronic load limiters or mechanical overload clutches.
2)Anti-Sway Control
Purpose: Reduces load swinging during crane movement, improving load stability and operator safety.
Operation: The system uses sensors or encoders to detect the position of the load and adjusts crane motion (either speed or direction) to reduce sway.
Use: Particularly useful in high-precision operations or in environments with high winds.
3)Emergency Stop (E-Stop)
Purpose: Instantly stops crane operation in case of an emergency, preventing accidents.
Operation: When activated, the E-Stop shuts off power to the crane's motors, bringing the crane to a halt.
Location: E-Stop buttons are installed at accessible locations on the crane, operator's cabin, and remote control system.
4)Limit Switches
Purpose: Prevents the crane from traveling beyond safe limits, protecting it from collisions or structural damage.
Types:
Hoisting Limit Switch: Stops the hoisting motion at maximum hook height (prevents over-lifting).
Trolley Travel Limit Switch: Prevents the trolley from traveling beyond the girder ends.
Crane Travel Limit Switch: Prevents the crane from over-traveling on the ground rails.
5)Safety Latches and Hooks
Purpose: Prevents accidental release of loads during lifting operations.
Design: A spring-loaded safety latch is attached to the hook. It automatically closes to secure the load and prevents accidental detachment.
6)Anti-Collision Device
Purpose: Prevents collisions between the gantry crane and other equipment, structures, or cranes in the vicinity.
Operation: Proximity sensors or cameras detect obstacles and send alerts or stop crane movement to avoid contact.
Use: Often installed in areas with multiple cranes or narrow operating spaces.

11.Control Mode

1)Pendant Control (Wired Control)
Description: This is a traditional control method where the operator uses a wired pendant to control crane movements.
Operation: The pendant is connected to the crane's electrical system via a cable, allowing the operator to control hoisting, trolley movement, and crane traveling.
Features:
Simple and cost-effective.
Operator can control the crane from a safe distance but still close enough for manual intervention.
Limited movement range due to the tethered cable.
2)Radio Remote Control
Description: A modern control method that uses a wireless remote to control the crane from a distance.
Operation: The operator uses a handheld transmitter (often with a joystick or buttons) to control all movements, including hoisting, traveling, and stopping.
Features:
Allows the operator to move freely within a wide operational radius.
Increased safety as the operator can maintain a safe distance from the load or the crane itself.
Real-time feedback via the transmitter (LED indicators, load monitoring).
Can be integrated with alarm systems and emergency stop buttons for added safety.
3)Cabin Control (Operator Cabin)
Description: This is a standard control method where the operator sits inside a crane cabin and uses controls to operate the crane.
Operation: The cabin is mounted on the crane, and the operator uses joysticks, buttons, or levers to control all crane functions such as lifting, traveling, and slewing.
Features:
Provides a better view of the operational area and load.
Control over all crane movements with precision and comfort.
Cabin can be heated, ventilated, and soundproofed for operator safety and comfort.
Increased safety as the operator is isolated from dangerous areas.
4)Automated Control (Fully Automated Cranes)
Description: This mode involves using automated systems for controlling the crane, with minimal human intervention.
Operation: The crane is equipped with advanced sensors, cameras, and PLC (Programmable Logic Controller) systems. It follows predefined programs for repetitive tasks such as lifting, positioning, and movement along the track.
Features:
Precision and efficiency in lifting operations.
Ideal for high-volume or repetitive tasks in manufacturing plants, container ports, and warehouses.
Reduced operator error and labor costs.
Can include remote monitoring, diagnostics, and troubleshooting systems for performance tracking.
Safety features like collision avoidance systems, load monitoring, and emergency stopping.
5)Combined Control (Mixed Mode)
Description: A combination of manual and automatic controls, allowing the operator to switch between manual and automated functions based on task requirements.
Operation: The crane operates with manual control for tasks requiring human precision and control, but can be switched to an automated mode for repetitive, high-precision tasks.
Features:
Flexibility to adapt to various operational needs.
Can reduce manual labor while maintaining human oversight for safety.
Often used in complex or multi-functional operations.

12.Sketch

Main technical

1. High Load Capacity and Stability
Increased Load Capacity: The double girder design provides additional strength, allowing the crane to lift heavier loads compared to single girder cranes. This makes them ideal for heavy-duty applications.
Stability: The dual girders distribute the load evenly, providing greater stability during operations and reducing the risk of tipping over.
Ideal for Large Projects: Excellent for industries that require lifting and moving large or heavy materials, like construction, shipbuilding, and steel mills.
2. Enhanced Reach and Flexibility
Wider Span: Double girder cranes can be designed to cover larger spans, making them capable of reaching a greater distance for lifting and moving materials. This is particularly useful for wide workspaces like storage yards, docks, and factory floors.
Flexible Operation: These cranes can be fitted with a variety of lifting mechanisms, such as trolleys, hooks, or specialized lifting attachments, making them adaptable for different lifting needs.
3. High Lifting Speeds and Precision
Faster Hoisting: The design of a double girder crane allows for higher hoisting speeds compared to single girder cranes, improving overall efficiency during material handling.
Precise Control: With advanced control systems (like PLC-based control and load moment indicators), double girder cranes offer precise lifting control with minimal sway, making them suitable for high-precision tasks.
4. Durability and Long Lifespan
Robust Construction: Double girder cranes are made from high-strength steel, making them more durable and resistant to wear and tear than single girder cranes.
Heavy-Duty Design: Suitable for continuous and heavy lifting, the design ensures long-term operational reliability, especially in harsh environments like outdoor ports, steel mills, and construction sites.
Lower Maintenance Costs: Due to their high-quality construction, double girder cranes often require less maintenance compared to other types of cranes.
5. Versatility in Application
Multi-Functionality: These cranes are versatile and can be used in various applications, including material handling in ports, warehouses, construction sites, steel processing plants, shipyards, and power plants.
Adaptable to Different Environments: Whether used indoors or outdoors, these cranes can operate in diverse weather conditions and can be equipped with additional features like anti-collision systems, wind sensors, and remote monitoring.

1. Ports and Container Terminals
Cargo Handling: RMG cranes are commonly used in container ports for loading and unloading containers from ships to trucks or storage yards. Their high lifting capacities and long reach allow them to efficiently handle large containers and bulk cargo.
Stacking and Storage: These cranes are also used for stacking containers in container yards. They can move containers over long distances and place them in precise stacking positions, optimizing the use of space.
Ship-to-Shore Operations: Double girder gantry cranes are ideal for ship-to-shore operations, as they can efficiently transfer heavy loads between ships and docks, especially in busy container terminals.
2. Construction and Heavy Industry
Steel Mills and Foundries: In industries such as steel production, metal fabrication, and foundries, double girder cranes are used for lifting and transporting heavy steel billets, ingots, and machinery parts.
Construction Sites: These cranes play a crucial role in heavy construction projects, including the movement of large building materials, prefabricated elements, and structural components. Their high lifting capacity allows them to handle large and heavy loads, such as steel beams and concrete panels.
Heavy Equipment Handling: Double girder gantry cranes are often used in industries that require handling of heavy equipment and machinery, such as during the assembly and maintenance of large machines.
3. Shipyards
Shipbuilding: In shipyards, RMG cranes are used to assemble large ship parts and move them within the yard for further fabrication. They can lift and position hull sections, engine components, and other large, heavy materials.
Ship Repair and Maintenance: These cranes are also useful for ship repair operations, as they can lift heavy ship parts (such as engines or other machinery) to be replaced or repaired.
Launch Operations: They are often used to assist in the launching of ships by lifting sections of ships or moving them along assembly lines to the water.
4. Manufacturing and Assembly Lines
Automotive Manufacturing: In the automotive industry, double girder cranes are used for assembling car parts or moving car bodies along the production line. Their high capacity allows them to handle multiple components simultaneously.
Assembly Line Support: These cranes help move heavy equipment and materials along manufacturing processes. They assist in assembling large equipment, moving parts to different production stages, or transferring finished products for packaging and shipping.
Warehouses and Distribution Centers: For high-volume material handling, these cranes help lift and transport heavy goods, including raw materials, finished products, and bulk loads within large warehouse environments.
5. Steel Mills and Foundries
Material Handling in Steel Mills: These cranes are used in steel mills for lifting heavy metal billets, slabs, or hot metal ladles. The robust design allows the crane to work in extreme environments where high temperatures and heavy lifting are common.
Casting and Furnace Operations: They are essential for casting operations, lifting heavy molten metal ladles or transporting cast iron, steel ingots, and foundry products from one station to another.
Steel Handling: In steel processing plants, double girder gantry cranes move steel coils, sheets, and structural steel around the factory for storage and shipping.
6. Agricultural Industry and Fertilizer Plants
Bulk Material Handling: These cranes are also used in industries such as agriculture, fertilizer plants, and chemical plants, where they help in loading and unloading bulk materials like fertilizers, grains, or heavy raw materials from storage to transport vehicles.
Silos and Storage: In these environments, the crane is used to move heavy loads of raw materials or finished products from silos or storage units to packaging or loading stations.
7. Logistics and Transportation
Bulk Cargo Handling: Double girder gantry cranes are often used in logistics hubs and cargo yards to load and unload heavy items, bulk cargo, and large freight containers.
Automated Distribution: In automated logistics centers, these cranes are essential for moving large containers and items between different sections of the warehouse or loading bays.
Heavy Freight Handling: Ideal for heavy freight transport, such as moving oversized components like machinery, large vehicles, and engineering products.

1.Design and Engineering: Initial planning and customization.
2.Material Selection: Sourcing of high-quality materials.
3.Fabrication: Cutting, shaping, and welding of the structure.
4.Assembly: Installation of key components like the hoist, trolley, and control system.
5.Painting and Corrosion Protection: Surface treatment and application of protective coatings.
6.Testing: Static and dynamic testing for load capacity and safety features.
7.Final Assembly and Commissioning: Final assembly and setup for operational testing.
8.Quality Control and Delivery: Final inspections, packing, and delivery to the customer.
9.Post-Installation Support: Ongoing support, including training and maintenance.

Workshop view:

The company has installed an intelligent equipment management platform, and has installed 310 sets (sets) of handling and welding robots. After the completion of the plan, there will be more than 500 sets (sets), and the equipment networking rate will reach 95%. 32 welding lines have been put into use, 50 are planned to be installed, and the automation rate of the entire product line has reached 85%.