The term 30kg rail refers to a rail section with a nominal weight of approximately 30 kilograms per meter. Compared with lighter options such as 18 kg or 24 kg rails, the 30kg light rail offers significantly improved load-bearing capacity and structural stiffness while keeping installation efficient and cost controlled. Manufactured in accordance with Chinese GB railway standards, this rail type ensures consistent dimensions, stable mechanical properties and reliable compatibility with standard railway fasteners.
What Is a 30kg Rail
The 30kg rail is the top section of the GB light rail family defined in GB/T 11264-2012. It is a flat-bottom section with a height of 107.95 mm, head width of 60.33 mm, bottom width of 107.95 mm and web thickness of 12.3 mm, with an actual mass of about 30.1 kg/m. It is designed for medium-load lines where lighter rails are insufficient but full heavy rail sections are not required.
Material Grades and Mechanical Properties
The 30kg rail is normally supplied in Q235B or 55Q steel. Q235B is a standard carbon structural steel with good weldability, while 55Q is a higher-strength rail steel with better wear resistance for busier lines. Representative mechanical properties are listed below.
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Elongation | Hardness |
|---|---|---|---|---|
| Q235B | ≥ 235 | 375-460 | ≥ 26% | - |
| 55Q | ≥ 685 | Verified per standard | Per standard | ≥ 197 HBW |
Chemical composition is controlled to guarantee these properties, including carbon content of 0.12-0.22% for Q235B and 0.50-0.60% for 55Q, with phosphorus and sulfur held to low limits.
Light Rail Dimension Series
The 30kg rail belongs to a complete GB light rail series. The table below compares the sections commonly supplied.
| Section | Height (mm) | Head (mm) | Bottom (mm) | Web (mm) | Weight (kg/m) |
|---|---|---|---|---|---|
| 18 kg/m | 80 | 40 | 80 | 10 | 18.06 |
| 22 kg/m | 93.66 | 50.8 | 93.66 | 10.72 | 22.3 |
| 24 kg/m | 107 | 51 | 90 | 10.9 | 24.46 |
| 30 kg/m | 107.95 | 60.33 | 107.95 | 12.3 | 30.1 |
Application Scenarios
The 30kg rail is particularly suitable where higher stiffness and durability are required without excessive cost. Typical uses include medium-load industrial railways, mining tracks, material handling lines and factory internal transport systems. For light-duty transport, 18-24 kg sections are normally sufficient; for heavy-duty lines, sections of 38 kg/m and above are recommended.
Selection Criteria and Common Misconceptions
Select the rail weight according to axle load, traffic intensity and service life targets. When installing the 30kg rail, match the fasteners, joint bars and sleepers to the section: standard clips and bolts for 30kg rails, standard fishplates for joints, and steel or concrete sleepers with the correct baseplate. Field welding is applicable with qualified procedures. Proper installation ensures smooth operation, reduced vibration and extended service life.
A common mistake is assuming the 30kg rail can replace heavier sections on main lines; its section modulus is designed for medium loads only. Another is mixing fasteners designed for different rail sections; the head and bottom geometry of each rail requires matching components.
Frequently Asked Questions
What is a 30kg rail? GB light rail section with a nominal weight of about 30 kg/m, defined in GB/T 11264-2012.
What materials are used for 30kg rails? Q235B carbon structural steel or 55Q rail steel, depending on the required strength and wear resistance.
What are the dimensions of the 30kg rail? Height 107.95 mm, head 60.33 mm, bottom 107.95 mm, web 12.3 mm, with an actual mass of about 30.1 kg/m.
Where is the 30kg rail typically used? On medium-load industrial and mining railways, factory lines and material transport systems.
Can 30kg rails be welded? Yes, field welding is applicable with qualified welding procedures, or fish plates can be used at joints.
