Large-tonnage crawler cranes are powerful cranes designed for lifting and moving heavy loads, operating on caterpillar tracks. These cranes are widely used in construction, energy, ports, mining, and other industrial applications. Here is detailed information about large-tonnage crawler cranes:

### Key Features
1. **Capacity**:
   - Large-tonnage crawler cranes have lifting capacities ranging from 50 tons to several thousand tons.

2. **Crawler Drive System**:
   - The crawler drive system allows cranes to move even on challenging terrain. These tracks enhance the crane's stability and provide a broader working area.

3. **Boom and Jib**:
   - Booms can be used to increase the lifting height and working radius of cranes. Different types and lengths of booms are available. Jibs can be added to the end of the boom to increase the lifting capacity and height.

4. **Counterweights**:
   - Various weights of counterweights are used to ensure balanced operation of the cranes. These weights enhance the stability and lifting capacity of the cranes.

### Applications
1. **Construction Industry**:
   - Used in the construction of tall buildings, bridges, and other large structures.

2. **Energy Sector**:
   - Employed for installing wind turbines, maintaining power plants, and transporting heavy generators.

3. **Port and Shipping**:
   - Used for loading and unloading large containers and other heavy cargo.

4. **Mining and Industrial Facilities**:
   - Used for transporting and installing large machinery and equipment.

### Advantages
1. **High Lifting Capacity**:
   - Capable of lifting very heavy loads, making them ideal for transporting large and heavy equipment.

2. **Mobility**:
   - The crawler system allows movement even on challenging terrain.

3. **Stability**:
   - Wide-based tracks and counterweights enhance the stability of the cranes, supporting safe operations.

4. **Versatility**:
   - Various boom and jib combinations allow for use in diverse applications.

### Disadvantages
1. **Large Size and Weight**:
   - Transporting and setting up these cranes can be time-consuming and costly.

2. **High Cost**:
   - Purchasing and operating costs are quite high.

### Maintenance and Safety
- **Maintenance**:
  - Regular maintenance of crawler cranes is critical for safe and efficient operation. This includes hydraulic systems, engines, tracks, and other essential components.

- **Safety**:
  - It is important for operators to receive proper training and adhere to safety procedures. Additionally, loads must be properly balanced, and cranes must be correctly set up.

### Leading Manufacturers
1. **Liebherr**: Germany-based manufacturer of high-capacity crawler cranes.
2. **Terex**: US-based manufacturer of various construction machinery and cranes.
3. **Manitowoc**: US-based global crane manufacturer.
4. **Sany**: China-based manufacturer of a wide range of construction machinery.
5. **Zoomlion**: China-based manufacturer of heavy machinery and equipment.

Large-tonnage crawler cranes ensure the safe and efficient transportation and lifting of heavy loads in industrial projects. With proper use and regular maintenance, these cranes offer ideal solutions for a wide range of applications.