## Common ground
All are types of railway or tramway sleepers used to support rails and maintain track gauge.
## Options at a glance
**4406 – Made of wood**
- **Defining trait:** Constructed from natural timber, typically treated for durability.
- **Typical examples:** Wooden ties used in traditional rail tracks.
- **Best fit when:** The sleeper is made primarily of untreated or treated wood, commonly found in older or low-speed lines.
**6810.99 – Made of cement concrete or artificial stone**
- **Defining trait:** Manufactured from reinforced concrete or similar synthetic materials, offering high durability and longevity.
- **Typical examples:** Pre-cast concrete sleepers used in modern rail systems.
- **Best fit when:** The sleeper is rigid, heavy, and made of poured or molded concrete with embedded reinforcement.
**7302.90 – Made of iron or steel**
- **Defining trait:** Constructed from ferrous metals, often used for high-load or specialized tracks.
- **Typical examples:** Steel rail chairs or metal sleepers in industrial or temporary track systems.
- **Best fit when:** The sleeper is metallic, typically bolted or welded to rails, and used in heavy-duty or temporary applications.
## Key differences
| Feature | 4406 (Wood) | 6810.99 (Concrete) | 7302.90 (Steel) |
|---------------------|-------------------|--------------------|---------------------|
| Material | Natural timber | Concrete/artificial stone | Iron/steel |
| Weight | Lighter | Heavy | Medium to heavy |
| Durability | Moderate | High | High (but prone to rust) |
| Common use | Traditional tracks | Modern mainlines | Industrial/temporary |
## How to choose
- Is the sleeper made of natural wood? → 4406
- Is it a solid, heavy, pre-cast block of concrete? → 6810.99
- Is it metallic and likely bolted or welded to rails? → 7302.90
## Overlaps & pitfalls
A sleeper may combine materials (e.g., steel-reinforced concrete), but the primary material determines the HS Code. If unclear, prioritize the dominant structural material. No option is vague—each reflects a distinct construction type