RTG Crane Technical Specifications & Parameters
GB/T 19912-2005, the Chinese national standard for Rubber-Tired Gantry Cranes (RTGs), is the definitive product specification for this equipment type. It defines type parameters, technical requirements, safety device configurations, and test methods, serving as the core reference for the design and selection of container yard lifting equipment.
GB/T 19912-2005, issued in 2005, is the dedicated product standard for Rubber-Tired Gantry Cranes (RTGs). Unlike rail-mounted cranes, RTGs use solid rubber tires for travel within their large-span portal frame, offering superior maneuverability, eliminating the need for crane rails, and providing greater flexibility in yard layout. This makes them one of the most critical pieces of handling equipment in container terminals. The standard applies to the design, manufacturing, and acceptance of RTGs with a rated lifting capacity of 30.5 to 50 tons and a span of 23.5 m (capable of spanning 6 container rows plus one truck lane). Kelude Heavy Industry manufactures custom RTG equipment in accordance with this standard.
RTG Type Classification and Key Parameters
The standard specifies the type classification and basic parameter series for RTGs. Based on the hoisting mechanism, RTGs are classified into wire rope drum hoisting types (standard lifting speed of 15–23 m/min, suitable for general container handling) and hydraulic hoisting types (offering higher precision but slower speeds, intended for special container operations). Based on the trolley travel system, they are classified into rope-towed trolley types (where the trolley is pulled along the main girder by wire ropes, offering a lightweight structure and representing the current mainstream RTG design) and rack-and-pinion driven trolley types (providing more reliable drive, suitable for large hoisting heights and high-frequency operations). The standard rated lifting capacity series includes five levels: 30.5t, 35t, 40.5t, 45t, and 50t. Standard spans are 23.47 m (for 6 container rows + 1 truck lane) and 26.5 m (for 7 container rows + 1 truck lane). Standard lifting heights are 12.2 m (for stacking 4 tiers of empty containers), 15.2 m (for stacking 5 tiers of loaded containers), and 18.2 m (for stacking 6 tiers of loaded containers).
Key RTG performance parameters include: crane travel speed is typically 25–35 m/min under no-load conditions and 15–25 m/min under full load. The travel wheels use solid rubber tires (common specifications range from 7.00-12 to 12.00-20), with a tire pressure of 0.7–0.9 MPa. Cross travel speed is 40–80 m/min. Hoisting speed is 15–23 m/min under full load and 30–40 m/min under no-load. The spreader is a telescoping container spreader (switchable between 20ft and 40ft), and its hydraulic system operates at a working pressure not exceeding 20 MPa. The total installed power for an RTG typically ranges from 200 to 400 kW, with power supplied either by a diesel generator set (rated approximately 250–500 kVA) or via a cable reel. Diesel generator sets must be equipped with silencers and exhaust gas purification devices to reduce noise and emissions in the terminal environment.
Structural and Mechanical Design Requirements
The RTG's metal structure consists of the portal frame (main girder plus outriggers) and the bottom chassis frame. The main girder employs a box or truss structure. Given the large span of the RTG (over 23.47 m), the static deflection under full load must not exceed L/600. The outriggers are designed in an L-shape or A-shape configuration. The connection nodes between the outriggers and the main girder must undergo fatigue strength verification, as the high operating cycle frequency of RTGs (20–30 cycles per hour) makes structural fatigue a critical concern. The bottom chassis frame connects the two sides of the outriggers into a single unit, withstanding the torque and bending moments generated during crane travel. The rubber-tired travel system comprises a drive axle and a steering axle—typically the front axle is the drive axle and the rear axle is the steering axle, although configurations where both axles are drive-steer axles are also used. The standard specifies that the RTG's steering system must enable right-angle steering for lateral movement between yard blocks, with each steering action completed in no more than 30 seconds. The travel system must be equipped with a tire pressure monitoring system.
The safety device configuration for RTGs is more comprehensive than that of general-purpose gantry cranes. Mandatory safety devices include: an overload limiter (the container spreader must be equipped with an electronic weighing device with an accuracy of ±2%), a lifting height limit switch (the upper limit position of the spreader must be no less than 500 mm from the trolley frame), a crane travel limit switch (to decelerate and stop the crane when approaching the yard boundary), trolley travel limit switches (with buffers and limit switches at both ends of the trolley travel), an anti-sway system for the spreader (mechanical or electronic systems to reduce load swing during operation and improve handling efficiency), an anemometer (to automatically alarm when wind speed exceeds 16 m/s and automatically cut off power to the crane travel system when wind speed exceeds 20 m/s), emergency stop buttons (one in the operator cabin and one at ground level), and anti-collision radar or laser distance measurement devices (to prevent collisions between multiple RTGs operating in the same yard).
Electrical & Control System Requirements
The electrical control system of an RTG is considerably more complex than that of a standard crane. The standard specifies that an RTG shall be equipped with a programmable logic controller (PLC) for full-machine automatic control and fault diagnosis. Core control functions include: closed-loop speed control of the hoisting mechanism—using encoder feedback to achieve precise speed regulation and position positioning; automatic trolley positioning and skew correction—detecting trolley position via laser or encoder to automatically correct skew and ensure accurate spreader-to-container alignment; and crane travel skew correction—monitoring rotational speed differences between travel wheels on both sides and automatically adjusting to prevent the RTG from traveling at an angle. All mechanisms shall adopt variable-frequency speed control for smooth starting and stopping to minimize load swing. The operator's control station in the cabin shall be equipped with a color touch screen (HMI) displaying operating status parameters and fault information for all mechanisms. The diesel generator set shall feature automatic start/stop and load management capabilities.
The standard also requires remote monitoring and communication capabilities for the RTG. The RTG shall be equipped with a wireless communication system to interface with the terminal's container operations management system (TOS), enabling real-time receipt of work instructions and automatic upload of operational data. Spreader weighing data shall be automatically recorded and transmitted to the management system. Fault alarms from the RTG shall be sent in real time to the maintenance center via the wireless network. Operating hours and lifting cycle counts for each mechanism shall be automatically logged to support equipment maintenance planning. The standard further imposes stricter electrical safety requirements on RTGs—given their outdoor, all-weather operation, all electrical components shall have a protection rating of no less than IP55, and cables shall be marine-grade, resistant to marine atmospheric corrosion. The electrical room shall be equipped with an air conditioning system to maintain internal temperature at or below 40°C. The control system supplied with Kelude Heavy Industry RTGs features remote monitoring and fault self-diagnosis capabilities.
Test Methods and Acceptance Requirements
The standard specifies requirements for both factory routine tests and site acceptance tests for RTGs. Before delivery, each unit shall undergo a no-load test in which all mechanisms operate continuously at rated speed for 1 hour without abnormality. The rated load test (100% SWL) involves lifting the rated load and operating at typical working radii to measure main girder deflection (≤ L/600) and travel speed. The dynamic load test requires lifting 1.1 times the rated load with each mechanism performing no fewer than 5 cycles. The static load test involves lifting 1.25 times the rated load and holding for 10 minutes; after unloading, residual deformation shall not exceed L/2000. Specialized tests for the rubber-tire travel system include: straightness and skew-correction tests under both no-load and full-load conditions, a 90° steering test (to be conducted on a concrete test pad), and verification of the tire pressure monitoring system. Dedicated spreader tests include: telescoping function test (5 cycles each for 20 ft and 40 ft positions), spreader twist-lock open/close function test, weighing accuracy calibration (error ≤ ±2%), and anti-sway effectiveness verification.
Site acceptance testing shall be conducted at the container yard after installation and commissioning of the RTG is complete. Acceptance items include: straightness inspection of crane travel tire tracks (travel 50 m across the yard and measure track offset, which shall not exceed ±100 mm); ground bearing pressure measurement (shall not exceed the yard's ground load design value); diesel generator load test simulating full-load conditions for 2 hours with generator voltage and frequency fluctuation not exceeding ±2%; overall machine noise measurement—cabin interior noise shall not exceed 75 dB(A) and exterior noise at 1 m distance shall not exceed 85 dB(A); spreader-to-container alignment accuracy test—under rated load, the operator controls the spreader from the cabin to align with a target container, and accuracy shall meet operational requirements; and anti-collision system functional verification simulating automatic deceleration and stopping when two machines approach each other. Upon successful completion of all acceptance items, an acceptance report shall be issued as the basis for equipment delivery and put into operation.
RTG Core Parameter Comparison Table
The comparison table below lists the core parameter configurations for Rubber-Tired Gantry Cranes, for reference by selection and operation personnel.
| Lifting Capacity(t) | Span(m) | Lifting Height(m) | Lifting Speed(m/min) | trolley speed(m/min) |
|---|---|---|---|---|
| 30.5(Lifting spreaderlower) | 23.47 | 12.2(stack4pass5) | 12~18(Full load) | 50~70 |
| 35(Lifting spreaderlower) | 23.47 | 15.2(stack5pass6) | 15~23(Full load) | 50~70 |
| 40(Lifting spreaderlower) | 26.50 | 18.2(stack6pass7) | 15~23(Full load) | 50~70 |
| 41(Lifting spreaderlower) | 30.48 | 18.2(stack6pass7) | 12~18(Full load) | 40~60 |
FAQ
Q: What is the difference between an RTG and a Rail-Mounted Gantry Crane (RMG)?
A: An RTG runs on rubber wheels and can move freely between container rows, offering greater flexibility but lower load-bearing capacity. An RMG travels on steel wheels along crane rails, providing higher positioning accuracy and load capacity, but it cannot leave its fixed lane. RTGs are best suited for small to medium container yards, while RMGs are ideal for automated, large-scale terminals.
Q: What does the anti-sway system on an RTG do?
A: After the container spreader is hoisted, acceleration and deceleration of the crane bridge and trolley travel can cause the load to swing. The anti-sway system suppresses this oscillation using mechanical damping or electronic control, allowing the spreader to settle quickly and steadily. This significantly improves container handling efficiency and operational safety.
Q: What are the tire maintenance requirements for an RTG?
A: Tire pressure should be checked weekly and kept within the specified range. If tires show uneven wear, the crane bridge skew-correction system should be inspected. Tires must be replaced promptly when surface cracks appear or when tread wear reaches the wear indicators.
Q: How do I select the right diesel generator set for an RTG?
A: The diesel generator power rating should be 1.2 to 1.5 times the total power of all motor mechanisms. Peak power demand during full-load hoisting must also be considered. The fuel tank capacity should support 8 to 16 hours of continuous operation. Low-noise generator sets are recommended.
