- Jan 27, 2026
- News
Rubber Tired Gantry Crane for Container Handling
Boost container handling efficiency with a rubber tire gantry crane. Enjoy flexible movement, easy operation, and reliable performance—learn more now!
Rubber Tire Gantry Crane for Container HandlingA rubber tyre gantry crane (RTG) is a specialized heavy-lift crane designed for container yards. It spans multiple container lanes on a tall portal frame and runs on large rubber tyres, giving it exceptional mobility and flexibility in the yard. RTGs are dedicated to stacking, moving and retrieving ISO containers (typically 20ft, 40ft, or 45ft units) in ports and logistics terminals. They carry a telescoping container spreader that locks onto the container's corner castings to handle different lengths. Modern RTGs often integrate automation (such as auto-twistlock, automatic positioning and anti-sway systems) to improve safety and speed. In practice, RTGs let you move swiftly between rows and lanes without fixed tracks, unlike rail-mounted cranes, which maximizes yard flexibility.
RTG Crane Capacities, Specifications & Performance Parameters
1. Common RTG Crane Capacities
RTG container gantry cranes are offered in a wide range of lifting capacities. Most industrial models fall in the 20 to 60 ton range under the spreader. For example, Mi-Jack's Travelift RTG series includes 30t, 40t, 50t, 55t and 60t capacities. Some manufacturers even offer up to 65t single-lift RTGs for the heaviest loads. (Heavy-lift models can be used in tandem picks to handle well over 100t.) As a buyer, ensure the RTG's SWL (safe working load) exceeds your heaviest container plus a safety margin. In practice, many terminals standardize on 45–50t RTGs and use twin-lift spreaders for higher throughput (see below).
2. RTG Span Selection
The span of an RTG is the width it covers, typically measured in container rows plus one truck lane. Common RTG spans are 6+1 or 7+1 (six or seven container rows plus one truck lane beneath). For example, Yuantai's standard RTG spans are 18m or 35m. In general, RTGs are built for 5–8 container rows wide. When choosing span, ensure it fits your block layout: a 6+1 crane can service six storage lanes, while a 7+1 crane covers seven, etc. Wider spans let one RTG serve more rows, but increase cost and wheel load.
3. RTG Wheel Load and Ground Bearing Requirements
RTGs carry enormous weight on their tyres, so ground bearing is critical. A typical RTG may have 8 to 16 large rubber tyres. The crane's chassis uses multi-wheeled balance beams to spread the load, its RTG trolley runs on a multi-wheeled balancing beam that disperses wheel pressure and protects the yard floor. In practice, yards must be reinforced concrete designed for the RTG's wheel pressure (often 30+ tons per wheel). If the ground is weak or sloped, special reinforcing or a reefer mat is needed. When specifying an RTG, confirm the tyre footprint and design ground bearing per wheel, and prepare the yard accordingly.
4. RTG Working Duty Class (A4–A7)
Crane duty class (ISO 4301) defines how intensively it can work. Container RTGs typically require high duty ratings. Yuantai's RTGs are rated A6/A7, meaning heavy continuous service. Terminals with moderate work might manage with Class A4 or A5 cranes, but major ports usually use A6/A7 machines. When buying, ensure the duty class matches your operating pattern: A7 handles virtually continuous 24/7 moves, whereas A4–A5 suits lighter or seasonal use.
Yuantai Container Gantry Cranes
RTG Crane Components & Structural Engineering
1. RTG Main Girder Design Options
The main span of an RTG can be built as a single beam or a double girder. Single-girder RTGs have one large beam supported by portal legs; they are lighter and may be used for lower capacities. Double-girder RTGs have two parallel box girders and a cross-frame; this stiffens the structure for higher loads and taller lifts. The choice affects headroom and hook height: double beams can allow a higher lift under the spreader since the hoist can be mounted between the girders.
2. Portal Frame, Outriggers & RTG Portal Legs
An RTG's portal frame consists of two tall steel legs and cross-beams. The base of each leg usually has outriggers with multiple wheels. Adjustable outriggers can be extended to lift the entire crane on its tyres (for turning) and then locked down to stabilize it. The portal legs themselves are massive welded box structures to resist bending and torsion. Some RTGs use a sloping A-frame shape or a vertical U-frame. The design of the portal determines how the crane handles heavy containers without twisting.
3. Rubber Tyre Steering System and Cross-Travel Behavior
Rubber-tyred gantry cranes can move in ways rail cranes cannot. The RTG's tires are often steerable and can turn in various modes. Yuantai's RTG have a variety of steering modes and even automatic deflection correction for straight travel. In practice, an RTG can crab, go lateral (sideways) between container stacks, or pivot 0–90° in place. This lets the RTG reposition across rows without moving the crane's base. When planning yard operations, this cross-travel means a single RTG can slide its spreader from one row to the next without realigning the crane.
4. RTG Trolley, Hoisting Gearbox, and Mechanical Drive System
The trolley runs on the gantry girder and carries the hoist and spreader. It is powered by motors and gearboxes that drum up hoisting ropes. The hoisting mechanism is mainly composed of motor, reducer, reel and wire rope, adopting double or multiple reels design, supporting rapid lifting and lowering. Dual or quad winches allow heavier lifts or faster speeds. The trolley's transverse movement along the main beam is usually by rack-and-pinion drive or a wire rope/rope drum system, with precision positioning. In summary, the RTG's hoisting gear is a robust multi-part unit (hoist motors, gearboxes, reels and brakes) designed for millions of cycles under heavy load.
5. Container Spreader for RTG Cranes
RTGs use telescopic container spreaders as the interface to the cargo. A spreader is a rectangular frame that extends (electrically or hydraulically) to fit 20ft, 40ft or 45ft containers. It has rotating twistlock corners to clamp onto the container. Modern RTG spreaders usually lock automatically; the operator simply lowers the spreader onto the container and it auto-twists and locks. The spreader often includes sensors and load cells for positioning. Overall, the spreader is critical hardware: keep its sensors, motors and twistlocks well-maintained to avoid downtime.
5.1 Single Lift, Twin-Lift, and Automatic Spreader Modes
Most RTGs operate in single-lift mode. However, many yards use twin-lift spreaders to double throughput. A twin-lift spreader can handle two 20ft boxes at once; it is effectively a double-box design. Such spreaders have adjustable center spacing in case containers aren't perfectly aligned. On the automation side, RTG spreaders often have auto-mode: the crane lowers the spreader and the twistlocks lock/unlock electronically, without manual interference. Combining twin-lift and auto-twistlock can greatly speed yard moves, though it increases the spreading hardware complexity. Your choice depends on yard density and whether you need to double-stack empty boxes.
5.2 Anti-Sway System for RTG Spreaders
To keep containers from swinging, RTG spreaders are typically equipped with anti-sway controls. These use sensors and active control algorithms to dampen any pendulum motion when the crane or hoist moves. As noted above, automatic anti-sway is often integrated in modern RTGs. This lets operators move loads more quickly without waiting for sway to stop. In short, an RTG with anti-sway can place containers more accurately and at higher speeds than one without.
6. PLC Control System and Automation Level
Rubber-tyred gantry cranes use sophisticated control systems. All motions are typically managed by a PLC (programmable logic controller) with AC variable-frequency drives on the motors. In practical terms, the operator's cabin has a joystick console and/or screen controls tied to the PLC. Many RTGs now include automated functions: auto-positioning of spreader, auto-lane steering, RFID or GPS guidance, etc. The PLC can also be connected to yard management systems.
7. RTG Steering Control & Cross-Drive Modes
Operators can select steering modes via the control panel. Common modes include 2-wheel steer, 4-wheel steer, and crab steer (all wheels steered equally). There may also be a drive diagonally mode. Coupled with these, cross-driving (moving lateral between rows) is achieved by turning wheels perpendicular. In all cases, the goal is to position the crane quickly: e.g. an operator can crab-diagonal the RTG to shift it sideways. This flexibility is unique to tyre-gantry cranes. Regardless, the RTG's traction motors and steering hydraulics must be well-tuned for smooth omni-directional moves.
8. Driver Cabin Ergonomics & Visibility Optimization
Good cabins offer panoramic visibility (especially downward and to the sides) so the operator can see spreader corners, trucks and workers. Glazing is designed with large, heated front windows and wipers to maximize sightlines even in rain or fog. Ergonomics are also important: adjustable seats with lumbar support, intuitive joysticks, and clear instrument panels reduce fatigue during long shifts. In short, the cabin should be climate-controlled and vibration-isolated, with well-placed controls so the operator can quickly and safely maneuver the RTG and spreader.
9. RTG Safety Monitoring System and Smart Diagnostics
Modern RTGs incorporate a variety of built-in safety features. Typical systems include overload protection and limit switches on travel and lift motions. Emergency stop buttons are placed around the frame and cabin. RTGs may also have audible and visual alarms (horns, strobe lights) for pedestrian alerts. More advanced features include proximity detection or anti-collision sensors. Additionally, self-diagnostics monitor critical systems (hydraulics, electronics) and can log errors or maintenance alerts. Daily inspection typically checks tyres, brakes, ropes, safety switches and hydraulics. Overall, a robust safety and monitoring system is essential in busy multi-RTG yards.
Power & Energy Options for Rubber Tyre Container Gantry Cranes
1. Diesel RTG Crane: Conventional Power Systems
Diesel RTG Crane: Conventional Power Systems The most common RTG power source is on-board diesel. There are two main approaches: diesel-electric and diesel-hydraulic. In a diesel-electric RTG, a diesel engine drives an electrical generator; AC electric motors then power the wheels and hoist. This configuration (often with inverter drives) offers high efficiency and good speed control. Diesel-electric RTGs feature frequency conversion speed regulation, easy maintenance and are suitable for continuous heavy use. The alternative is diesel-hydraulic: the engine drives a hydraulic pump, and hydraulic motors move the equipment. Diesel-hydraulic RTGs have fast response and compact layout but are typically less fuel-efficient. Many RTGs use the diesel-electric type today, as it better supports emission controls and long runtimes.
2. Diesel-Electric RTG Crane: Hybrid Technologies
To cut fuel use and emissions, hybrid RTGs are emerging. These combine a diesel genset with onboard energy storage (batteries or supercaps). The small diesel runs primarily to charge the batteries, while the batteries handle peak loads and can capture regenerative energy. The system also recovers energy when lowering containers (regenerative braking). If you're investing in RTGs and want green credentials, hybrid systems are a strong option, especially if government incentives are available.
3. Full Electric RTG Crane (Zero-Emission Yards)
A Full Electric RTG Crane is designed to eliminate diesel use while maintaining strong performance in container yards, and it can be powered in several proven ways. One option is a cable reel system, where a powered retractable cable feeds electricity to the RTG as it moves and rewinds when it returns. This solution makes the RTG fully electric with minimal changes to the crane structure and no major civil works, but it limits operation to fixed blocks and adds some weight and mechanical complexity. Another option is busbar electrification, which uses conductor rails installed along container lanes to supply continuous three-phase power through a current collector. This system allows smooth operation within dedicated lanes, avoids cable handling, and has become the preferred choice for new E-RTG projects worldwide due to its reliability and efficiency. A third approach is battery-assist or battery RTGs, where onboard batteries power the crane and recharge at plug-in stations, or support hybrid operation by storing regenerative energy. While batteries add weight and require charging infrastructure, they remove local emissions entirely and offer maximum operational flexibility.
RTG Crane Applications in Container Handling
1. RTG Ship-to-Stack Handling
In large ports, ship-to-shore (STS) cranes handle the vessel. RTGs typically operate in the yard, moving containers after they are landed by STS units. In smaller ports, an RTG may straddle both the quay and yard and perform a limited ship-to-stack service, but this is uncommon. Instead, RTGs excel at transferring containers between storage stacks and street trucks. In a typical workflow, a ship's containers are unloaded onto trucks or trailers, which then drive into the RTG's span; the RTG picks the container from the truck and moves it to the storage block. Conversely, outbound trucks arrive under the RTG, which loads them from the yard.
2. RTG Stack-to-Truck Transfer Operations
A primary use of RTGs is feeding trucks with containers for delivery. In this mode, RTGs operate along the yard's edge lanes. The operator picks a container from the storage block (stack-to-stack or reshuffle) and then sets it directly onto a waiting truck or trailer. Many container terminals reserve specific lanes under the RTG span for truck pick-up. This stack-to-truck transfer is usually scheduled: the terminal's management system dispatches a truck to a designated RTG lane, and the RTG operator loads it. Efficient coordination minimizes truck wait time. RTGs can also stage multiple trucks in a lane, swapping containers to keep all chassis moving.
3. RTG Short-Haul Movements Inside the Yard
Within the yard, RTGs also perform short-haul moves. If a container needs repositioning, an RTG can pick it up and carry it a short distance. Some terminals use one RTG as a shuttle across blocks. Because of their mobility, RTGs reduce the need for supplementary vehicles for intra-yard transfers of full containers. Note however that RTGs require at least one lane to drive on, so yard layouts must accommodate their paths even for short moves.
4. Typical Yard Layouts for RTG Operations
RTGs are usually deployed in blocks of container stacks. A common layout is a 1-over-6 stacking pattern in each block, with a wide drive lane underneath. For example, a 7+1 block has seven rows of containers and one truck lane under the RTG span. Generally, yard designers balance density and accessibility: 6+1 or 7+1 are typical. An RTG will shuttle along that drive lane. If multiple RTGs are used, often each is assigned to its block. Optimizing traffic means separating lanes for trucks and for empty re-positioning, and marking clear cross-travel areas. Some yards even automate yard cranes so that the path planning can avoid congestion. In all cases, allow sufficient turning and stepping areas in each block for the RTG to maneuver.
Optimizing Yard Traffic Around Rubber Tyre Gantry Cranes
In an RTG yard, keep trucks on designated lanes and limit cross-traffic. Use signage and yard dispatch to ensure trucks enter under the correct crane. If multiple RTGs operate in one block, anti-collision interlocks or simple zone restrictions are important. Also, prevent pedestrians or forklifts from wandering under an active RTG span. Since RTGs can change blocks relatively easily, you might move an RTG to different areas during low-traffic periods to balance the work. In sum, plan clear lanes and signals: rubber-tyre gantry cranes bring flexibility, but that must be managed by good yard layout and traffic rules.
RTG Crane Safety, Inspection & Compliance
1. RTG Safety Systems and Alarm Functions
Safety on an RTG relies on multiple layers. Standard features include lift and travel alarms. On the equipment side, sensors and limit switches prevent over-travel. This means if a container is too heavy, or if a travel limit is reached, the crane cuts power. Emergency stop buttons (E-stops) are located in the cabin and on the frame. Ensure your RTG has clear audible and visual warnings to alert nearby workers when it's moving. In multi-RTG yards, anti-collision logic is increasingly used to prevent crashes.
2. Overload Protection, Limiters & Emergency Stops
Each RTG spreader includes a load limiter to prevent lifting beyond rated capacity. The control system should sound an alarm if overload is detected. In addition, mechanical latches or brakes lock the hoist automatically if a limit is reached. For travel, ensure the RTG has programmable limit stops at aisle ends, so it can't overrun the block. Emergency stop circuits should cut all motion in any direction when triggered. At Yuantai Cranes, these safety devices are standard.
3. Anti-Collision Systems for Multi-RTG Yards
When two RTGs operate in the same area, collisions are a risk. Many modern RTGs offer anti-collision systems. If you are operating multiple RTG cranes in the same area, a specific device is required to restrict one RTG crane from entering the operating area of another. Even without high-tech gear, floor markings, lights, and strict operating rules help.
4. RTG Driver Cabin Safety Features & Ergonomics
The cabin itself must meet safety standards. Features include roll-over protection structures, safety glass, seat belts and slip-resistant flooring. All controls should be clearly labeled. Ergonomically, the driver's seat should be adjustable with shock absorption to reduce fatigue. Also ensure the cabin has good climate control and filtration for dust, fumes or salt air. Visibility aids are important. Emergency egress must be accessible.
5. RTG Daily Inspection Checklist
A daily check list is crucial for safe RTG operation. Typical items include: tyre condition and pressure; brake function; hydraulic oil levels; hoist brake and rope condition; limit switch operation; spreader twistlock operation; lights and alarms; and general structural checks (any cracks or loose bolts). The operator should inspect the tyres and steering for any jamming or wear each morning. Check that the emergency stops work. Verify all safety sensors and interlocks are responsive. Any defect must be fixed before use. Many terminals post a daily stamp in a logbook when the RTG passes inspection. Regular inspections catch small issues (like a frayed wire or low fluid) before they cause downtime or accidents.
Comparison & Purchasing Guidance
1. RTG Crane vs RMG (Rail Mounted Gantry)
RTGs and RMGs serve similar roles but in different scenarios. In essence, RTGs trade ultimate precision for flexibility. RTGs run on tyres and so can move blocks or lanes at will, whereas RMGs run on fixed rails with the most accurate movement. RTGs are usually diesel-powered and excel in smaller, flexible operations (you can reposition them anywhere). RMGs operate on rails and are typically electric; they offer very precise stacking and are better suited for very large, fixed-layout terminals. In practice, choose RTG if you need mobility or have budget constraints. Choose RMG if you will run 24/7 at huge volume on a fixed grid.
2. RTG vs Straddle Carrier Comparison
Straddle carriers are rubber-tyred vehicles that lift containers from underneath. They are self-propelled and do not require fixed lanes. Straddles are agile and fast for point-to-point moves. They are ideal for medium-sized yards and make short intra-yard transfers (quay-to-stack) very flexible. In contrast, RTGs handle full blocks with higher capacity and density but require designated lanes. Straddles use more yard space per unit and generally have lower lift heights, but can go anywhere. RTGs take up one lane but stack more containers with one machine. Use straddles if you need extreme flexibility and lower throughput; use RTGs if stacking density and throughput are priorities.
3. When to Choose Rubber Tyre Gantry Cranes for Your Terminal
Consider RTGs when your terminal requires high stacking and moderately high throughput but also needs layout flexibility. They are also good if operations are intermittent (you can drive them to a safe zone after use). Avoid RTGs if you need absolute precision automation or extremely high moves per hour; in those cases RMGs or STS cranes might be better. Also ensure your ground is strong enough – RTGs need hefty pavement.
Frequently Asked Questions (FAQs)
Q: What advantages do rubber-tyred gantry cranes (RTGs) offer?
A: RTGs are highly mobile and can be moved between blocks easily, unlike rail-mounted cranes. They provide high stacking density and fast operations, while requiring no rails. This flexibility means you can reconfigure your yard layout if needed. RTGs are also generally cheaper to install (no rail foundation), and multiple cranes can share blocks. On the down side, RTGs have heavy tyre maintenance and usually rely on diesel (unless electrified). Overall, RTGs suit yards that need both capacity and flexibility.
Q: How do RTGs differ from straddle carriers?
A: A straddle carrier is a self-propelled forklift-like vehicle that straddles one container. Straddles can pick up containers from anywhere in the yard and carry them over other lanes, which RTGs cannot do. They are very maneuverable and good for spot moves. RTGs, on the other hand, operate on fixed lanes and handle large blocks at once. RTGs typically stack higher and are better for continuous heavy lifting. Choose straddles for ultimate flexibility in small yards; choose RTGs for high-volume stacking in larger, denser yards.
Q: What maintenance is required for an RTG crane?
A: Regular maintenance is critical: daily inspections should cover tyre condition, brakes, safety devices (limit switches, E-stops), lights, and hydraulics. Grease all bearings and check wire ropes for wear. Every few weeks/months: change engine fluids, inspect steering linkages, test anti-sway and load limiter functions. Tyres need periodic replacement and alignment. The spreader's twistlocks, sensors and telescoping mechanisms also need scheduled check-ups. Following a preventive maintenance schedule (and keeping detailed records) maximizes RTG uptime.
Q: Can RTGs operate in an all-electric (zero-emission) mode?
A: Yes. New RTG designs allow fully electric operation via cable reels or busbar rails, or via batteries. With a cable reel, the crane uses a long power cable that unwinds as it moves (common on RMGs), giving continuous power without diesel. With a busbar (conductor rail) system, a live rail runs along the RTG's path and the crane draws power through a sliding collector. These systems require infrastructure but eliminate local emissions in the yard.
