A Comprehensive Knowledge Manual of Frame-type Railway Guardrail Nets

I. Core Definition and Structural Characteristics

1. Basic Definition:

Frame-type railway guardrail net is a high-strength protective structure specially designed for railway lines. It is composed of posts, frame mesh panels and connecting parts, and is fixed by bolts or welding to form a closed isolation barrier. Its core function is to prevent people and livestock from intruding into the railway boundary, resist the fall of foreign objects, and at the same time adapt to the complex terrain along the railway (such as mountains and Bridges).

2. Structural advantages

Rigid support: It adopts rectangular steel pipes or C-shaped steel frames, with an overall strength 30% higher than that of ordinary guardrail nets. It can withstand the vertical impact of a 50kg object from a height of 1.0m without damage.

Anti-climbing design: The mesh and the frame are integrally welded, eliminating the middle cross braces and reducing the number of borrowing points. The top can be equipped with a barbed wire roller cage (with a spacing of 100mm), significantly enhancing the anti-climbing performance.

Modular assembly: The standardized frame and columns are connected by anti-theft bolts, which increases the installation efficiency by 40% compared with the welded type and is convenient for later maintenance and replacement.

3. Typical structure

Column: Prefabricated C30 reinforced concrete (cross-section 120×120mm) or Q235 steel pipe (Φ60×4.0mm) is used, with a pre-buried depth of ≥500mm, and a C25 concrete base (500×300×300mm) is cast at the bottom.

Frame: The frame is made of 30×50×2.0mm rectangular steel pipes, with Φ4.0mm steel wire mesh (mesh size 75×150mm or 50×100mm) welded inside. The upper part is folded outward at a 30° Angle (vertical height 300mm) to enhance impact resistance.

Connecting parts: Made of 90° folded Q235 steel plate (4.0mm thick), the column and the frame are connected through anti-theft bolts (torque ≥30N · m). The screws need to be removed with special tools.

Ii. Core Materials and Craftsmanship

1. Material selection

2. Anti-corrosion process

Basic solution: Hot-dip galvanizing (zinc coating ≥85μm) + plastic coating (plastic coating 0.8-1.2mm), passing the 500-hour salt spray test, with a service life of 15-20 years.

High corrosion resistance solution: Hot-dip galvanizing (zinc coating ≥270g/m²) + double-layer plastic coating (inner layer PE, outer layer PVC), total plastic coating thickness ≥1.5mm, service life over 30 years, suitable for acid rain areas or high salt spray environments along the coast.

Iii. Technical Parameters and Selection Criteria

1. Key technical parameters

2. Basis for selection

Railway grade: For high-speed railways and passenger dedicated lines, 2.2m high frame mesh + barbed wire roller cages are selected, while for conventional railways, 1.8m high ordinary frame mesh is adopted.

Environmental conditions：Mountainous areas/windy regions: The column spacing is shortened to 2.5 meters, diagonal braces (45° Angle) are added, and the grade of the foundation concrete is raised to C30.

Coastal/chemical industrial zone: Galfan alloy steel wire + double-layer plastic coating is adopted, and the bottom of the column is wrapped with 300mm high PVC sleeve for anti-corrosion.

Functional requirements：

Anti-throw net (bridge section) : Mesh size ≤50×100mm, frame thickness ≥3.0mm, impact strength ≥1000N/mm².

Anti-falling rock net (high slope) : It adopts a flexible frame (steel wire rope + steel plate net), which can absorb more than 500kJ of impact energy.

Iv. Maintenance and Life Management

1. Daily maintenance

Monthly inspection: Focus on checking whether the weld points of the frame are cracked, whether the bolts are loose, and whether the plastic layer has fallen off. If any problems are found, repair welding or replacement should be carried out in time.

Quarterly cleaning: Remove debris from the surface of the mesh (such as leaves and soil), unclog the drainage holes of the frame to prevent water accumulation and corrosion.

Annual inspection：

The thickness of the galvanized coating is inspected (5 points are randomly selected per kilometer). If it is 80% lower than the standard value, re-galvanizing is required.

Random inspection of impact resistance performance (one site is selected every 5 kilometers), using a 50kg sandbag to freely fall from a height of 1.0m for testing. The deformation of the mesh ≤50mm is considered qualified.

2. Life cycle

Frame-type railway guardrail nets, with their high strength, easy maintenance and ecological friendliness, have become the mainstream choice for railway protection. In the design and construction process, it is necessary to strictly follow industry standards, optimize the plan in combination with specific environmental conditions, and ensure long-term safe and reliable operation.