Rtg rmg

Types of RMGs and RTGs

The key components and concepts of container handling are cranes and straddles, as they refer to two types of mobile cranes widely used to stack containers. The purpose of these machines is to move containers from and to the vessels at the port or from the terminal to a certain inland location. These types of machines are popularly known as RMG and RTG cranes.

The main difference between RMG and RTG lies in their power source and operational functionalities. The RMG cranes are mainly used to move containers between train tracks in terminals and to keep containers vertically on top of one another. On the other hand, the RTG crane are gantry cranes that retrieve or place containers from or to vessels, which makes them more widely used than the RMG crane.

Generally speakings, they both function the same, but their power sources and operational fields differ. Below is a more in-depth exploration of the details of the RMG and RTG cranes:

• Rail-Mounted Gantry Crane: RMG cranes are used in port terminals to stack containers. They are mainly used to move containers between train tracks and to keep containers vertically on top of one another. An RMG crane has the rails mounted to the ground. It runs on the rail tracks. It is most often used in combination with container bays adjacent to railway lines.
• Rubber-Tired Gantry Crane: RTG cranes are gantry cranes that retrieve or place containers from or to vessels, which makes them more widely used than the RMG crane. An RTG crane's wheels run on a paved surface. They are also used in port terminals to stack containers, but unlike RMG cranes, they are not restricted to rail tracks.

Specification and maintenance of RTG & RMG

Specification of RTG & RMG

• Flexible Cargo

  Typically, RTG cranes have the capacity to handle cargo ranging from 40ft to 60ft in length; however, they can also manage oversize and irregularly shaped items by extending the horizontal reach of the crane girders.

• Wide Gauge and Hook

  Hopper cranes are equipped with a hook and gauge that can be easily adjusted to lift different types of containers or cargo. They also feature a low base that facilitates the movement of containers from the yard directly onto the vessel, without the need for additional staging or equipment.

• Quick Return

  RTGs are designed to facilitate the horizontal and vertical movement of containers or cargo at high speeds. This is achieved through the use of advanced electrical and electronic control systems, as well as the application of anti-sway algorithms. These cranes can move at a speed of up to 90 meters per minute, and their stacking speed can reach up to 60 containers per hour.

• Stacking Height

  The typical stacking height of an RTG crane is between 6 and 7 containers. However, they can be configured to stack up to 11 containers high and have a reach of up to 13 containers. This is made possible by the use of multi-high systems, which allow for greater vertical storage capacity in container terminals and yards.

• Max Load

  Rubber-tyred gantry (RTG) cranes are capable of handling containers weighing up to 40.6 tons (40 short tons) when they are in full operational condition. This includes weighing the container itself, any cargo contained within it, and any other relevant factors.

Maintenance

• Routine inspections:

  Regular inspections of the crane should be carried out to ensure that any signs of damage, wear, or corrosion are promptly identified. All components, including structural parts, mechanical systems, electrical systems, hydraulic systems, and safety devices, should be thoroughly inspected. In addition, a schedule for inspections should be established based on the frequency and intensity of the use of the crane, and periodic maintenance and repairs should be carried out according to the inspection results.

• Lubrication and maintenance of moving parts:

  Moving parts, such as pulleys, bearings, and sliding tracks of the crane, should be regularly lubricated with the appropriate lubricant to reduce friction and wear. This ensures smooth operation of the crane. Cleaning and maintenance of electrical equipment and control systems should also be performed to prevent electrical faults and ensure reliable operation of the crane control system. Additionally, all wiring and connectors should be checked and any loose or corroded connections should be promptly addressed.

• Maintain a clean environment:

  It is important to keep the operating environment of the crane clean by promptly removing any foreign objects, debris, and dust to prevent blockages, abrasion, or damage to the crane.

Typical scenarios of using RTG/RMG cranes

Some common examples of how RTG cranes are used:

• In seaports, RMGs are used to transport containers from cargo ships to the terminal and vice versa. They can efficiently handle stacking and retrieval tasks in storage yards.
• Logistics centers employ RTGs to move goods between different modes of transportation, such as trucks and trains, and to manage inventory and fulfill orderShipping warehouses utilize RGMs to decant incoming shipments, sort packages, and facilitate the flow of goods to various distribution channels.
• Freight terminals utilize RMGs to handle containerized cargo from ships, trucks, and trains, ensuring smooth operations and efficient movement of goods.
• Manufacturing plants leverage RMGs to automate material handling processes, such as transporting raw materials, components, and finished products within the facility.
• Airport cargo facilities employ RMGs to manage air freight operations, handle cargo containers, and optimize the flow of goods to and from aircraft.

How to choose RTG/RMG

Choosing the right gantry crane for a port is crucial for efficient container handling and management. Several critical factors need to be evaluated before selecting an appropriate gantry crane for the port.

• Container Volume and Size:

The predominant purpose of a port gantry crane is to manage containers. Therefore, the volume and dimensions of the containers that need to be handled by the crane should be the first consideration when selecting a port crane. The size of the containers should also be considered so that the crane can be picked out and moved around the port alone with the containers.

• Maximum Lifting Weight:

When selecting a port gantry crane, the crane's maximum lifting weight must be taken into account. This is the most important consideration when selecting a port gantry crane, as it should be large enough to handle the heaviest of weights.

• Number of Ship Berths:

The number of ship berths at the port will also affect the selection of the gantry crane. This is important because ideally there should be one gantry crane to serve one ship berth, so that there is a smooth flow of operations without any delays.

• Available Space:

The amount of available space at the port will also play a big role in the selection of the gantry crane. If the space is limited, then a crane with a greater outreach must be selected so that there is sufficient coverage within the port area to handle incoming and outgoing containers.

FAQ

Q1: What is the difference between RMG and RTG cranes?

A1: The main difference between RM cranes and RTG cranes is the source of power and mobility. RMG cranes are rail-mounted, meaning they’re fixed to a track, which allows them to cover large areas of a facility. Conversely, RTG cranes are rubber-tired, which gives them greater flexibility and freedom of movement around a terminal or yard.

Q2: What are the future trends in straddle crane technology?

A2: The future of straddle cranes looks promising. Innovations like automated guided vehicles (AGVs) for seamless cargo movement, hybrid straddle carriers reducing carbon footprints, and predictive maintenance systems revolutionizing operational efficiency are just a few examples. As these advancements reshape industries, straddle carriers will remain pivotal in logistics and heavy cargo handling.

Q3: What are the benefits of using an RMG crane?

A3: The rail-mounted gantry crane has several benefits. They include high load capacity and lifting speed, efficient and economical operation, and suitability for heavy-duty and high-throughput applications. They also have the ability to stack containers, flexibility and adaptability, precision and automation, safety features, and sustainability through energy efficiency.