Railway cables are the “blood vessels” of urban transportation networks, and their performance is directly related to the safety and efficiency of the system. The underground and above ground environments are very different, and cable selection needs to be adapted to local conditions. This article starts from the laying environment, analyzes the core requirements for cable performance in different scenarios, and provides scientific selection strategies to help you accurately match engineering needs.
Laying environment challenges: underground humidity vs. above ground ultraviolet rays
01 Underground environment
High humidity and chemical corrosion: Underground tunnels are humid all year round, and some areas even have chemically corrosive substances (such as acidic water vapor in subway tunnels). Cable sheaths must have excellent waterproof, moisture-proof and corrosion-resistant properties.
Rodent risk: Underground rodents are active frequently, and cables must adopt anti-rodent bite structures (such as metal armor or adding rodent repellent coatings).
Space closure: Smoke is not easy to spread during a fire, and cables must have low smoke and halogen-free properties to reduce secondary hazards.
02 Ground environment
Ultraviolet rays and temperature changes: Cables laid outdoors need to resist long-term exposure to ultraviolet rays, and the sheath material needs to be resistant to aging (such as cross-linked polyethylene XLPE) and adapt to extreme temperature differences from -40°C to 70°C.
Mechanical stress: The elevated section is easily affected by wind and vibration, and the cable needs high tensile strength and wear resistance to avoid damage to the insulation layer due to long-term vibration.
Fire prevention and environmental protection: Although the ground line has better ventilation, it still needs to meet the low-halogen flame retardant requirements, taking into account environmental protection and safety.
Core performance requirements comparison and selection strategy
| Performance requirements | Underground scene | Ground scene | Selection strategy |
| Flame retardant | Halogen-free low-smoke Class A flame retardant, fire resistant for more than 90 minutes | Low halogen flame retardant, fire resistant for more than 60 minutes | Choose ceramic silicone insulated cable for underground and XLPE sheathed cable for aboveground. |
| Waterproof and moisture-proof | Double-layer sheath + metal armor, IP68 protection grade | Single-layer sheath + anti-ultraviolet additive | Preferably use copper sheath or aluminum-plastic composite tape structure for underground. |
| Rat and ant resistant | Metal armor or rodent-proof coating | Generally no special design required | Recommend TST CABLES rat-proof armored cable for underground, which complies with TB/T 1484.3 standard. |
| Weather resistance | Chemical corrosion resistance | Anti-ultraviolet, high and low temperature cycle resistance | Use TST CABLES cold-resistant/high-temperature resistant series cable for aboveground, which is suitable for -50℃ to 200℃. |
| Data transmission | High anti-interference shielding structure | Ordinary shielding structure | Use double-layer shielding + armoring design for underground, and single-layer shielding is sufficient for aboveground. |
TST CABLES: All-around solution for underground and aboveground scenarios
As a benchmark enterprise in the field of domestic rail transit cables, TST CABLES has become the first choice for projects with the following advantages:
Full-scenario adaptation:
Underground-only: Fire-resistant cables (such as the WDZN-TGJY series) use ceramic silicone insulation, with a fire resistance time of 3 hours, and halogen-free and low-smoke characteristics that perfectly match underground safety needs.
Overground-only: Weather-resistant cables (such as the EN50382 series) have passed the UV aging test, and the sheath life has been extended by 50%, adapting to extreme outdoor climates.
Technical certification guarantee:
Passed EN45545-2 (EU fire protection), GB/T 42740-2023 (safety guidelines) and CRCC certification, the performance far exceeds the national standard.
Environmental protection and cost advantages:
Domestic technology breakthroughs, 30% cost reduction, while meeting RoHS environmental protection directives, helping green rail transit.
The selection of underground and aboveground cables requires “the right medicine for the right disease”. Only by accurately matching environmental requirements can the safety line of rail transit be built. TST CABLES has been deeply involved in the industry for more than 10 years, using technology as a shield and innovation as a spear to provide full life cycle solutions for underground tunnels, elevated light rail and other scenarios. Choosing TST CABLES means choosing the dual guarantee of safety and quality!
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