How does a sealing system ensure high-speed trains run fast and smoothly?

When you ride a high-speed train, you might only care about the speed of the Wi-Fi, the comfort of the seats, and the scenery outside the window. But what worries engineers most are those unseen places—the undercarriage equipment compartment, the traction inverter, the connections between carriages… These places are filled with cables and pipes. If the seal fails, it can lead to signal interference and equipment malfunctions, or even water ingress, short circuits, and fires.

In the “extreme environment” of rail transit—high speed, high humidity, and strong vibration—the era of simply “pawing” with putty and tape is long gone. Today, TST SEAL, a professional-grade cable and pipe sealing system, is becoming the “invisible armor” for the safe operation of trains.

1. Undercarriage Equipment Compartment: A “Steel Fortress” in the Wind and Rain
The undercarriage is the dirtiest and most chaotic part of a train: rainwater, snow, flying stones, and the impact of airflow at speeds up to 350 km/h.

Solution: The TST SEAL IP68-level modular sealing and penetration system (such as the TST SEAL MTC solution) is adopted. Where cables pass through the car body, they are tightly sealed using intumescent fireproof sealing modules and a stainless steel frame. The materials used are EPDM rubber and austenitic stainless steel, resistant to -40℃ low temperatures, UV radiation, and salt spray corrosion.

Result: Even when speeding through torrential rain, the equipment compartment remains dry and clean. The Beijing-Zhangjiakou intelligent high-speed railway relies on this system to achieve 10 years of maintenance-free operation for its undercarriage equipment.

2. Traction Inverter & Auxiliary Converter: A “Silent Barrier” in the World of High Voltage Here, the voltage reaches thousands of volts, the current fluctuates wildly, and the electromagnetic noise is comparable to an “electromagnetic storm.” Meanwhile, the control board next to it has to handle millivolt-level signals—even slight interference could cause the train to “brake unnecessarily.”

Solution: All incoming and outgoing cables utilize MCT electromagnetic shielding sealing modules, achieving 360° ring grounding with a shielding effectiveness >80dB; It also integrates fireproof, waterproof, and shockproof functions, and has passed EN 50121 railway EMC certification.

Case Study: A high-speed train depot previously experienced frequent TCMS errors due to converter interference. After installing TST SEAL MCT modules, the annual failure rate dropped from 40 to zero, and maintenance costs decreased by 70%.

3. Control Cabinet Cable Entry: The “Security Gate” of the Signal System The driver’s cab and signal cabinet contain hundreds of cables: ATP, ATO, broadcasting, video… Interference in one cable can cause the entire train to lose connection.

Solution: Use modular multi-hole sealing plates, sealing each cable independently to avoid a domino effect; select halogen-free, low-smoke materials that do not release toxic gases in case of fire, meeting DIN 5510 and EN 45545 fire protection standards.

Trend: TST SEAL’s new generation control cabinet features “pre-installed sealing,” factory-prefabricated for plug-and-play operation on-site, improving installation efficiency by 5 times.

4. Inter-carriage Connectors: A Reliable Link Amidst Vibration
The carriage connection points are areas of greatest vibration and most frequent displacement. Ordinary connectors loosen after six months, leading to Wi-Fi disconnections and false door alarms.

Solution: Utilizing heavy-duty shielded connectors with flexible sealing sleeves, allowing ±15mm axial displacement; Double fluororubber sealing rings at the interfaces maintain elasticity even in extreme cold (-40℃).

Real-world Performance: After 10 years of winter operation on the Harbin-Dalian High-Speed ​​Railway, the inter-carriage communication link has remained uninterrupted, and passengers have never experienced buffering issues while watching videos.

Industry Trends: From “Import Substitution” to “Intelligent + Green”

Accelerated Domestic Substitution: Domestic brands such as TST SEAL and TST CABLE have fully replaced imports, reducing costs by 70%;

TST SEAL Modular Prefabrication: The sealing system is designed synchronously with the vehicle body, pre-assembled in the factory, and assembled on-site in a “Lego-like” manner;

Emerging Intelligent Monitoring: Some new trains are piloting the embedding of humidity/temperature sensors at sealing points to provide early warnings of aging risks;

Popularization of Green Materials: Halogen-free and recyclable sealing materials are becoming standard, contributing to the “dual carbon” goal.

Train Safety: Hidden in the Details
The safety of rail transit is never about “luck,” but about the perfect fit of every hole and the precise shielding of every cable. These seemingly small sealing systems are actually the cornerstone of high-speed, intelligent, and reliable train operation.

In the future, with the arrival of higher-speed trains such as the CR450 and maglev, the requirements for sealing will only increase. China’s TST SEAL sealing module technology is moving from “following” to “leading,” using its core strength to safeguard the safe travel of hundreds of millions of people.