Rail operators and rolling stock manufacturers continue to face increasing regulatory and operational pressure to improve fire safety, system reliability and passenger comfort. Fire protection standards are tightening globally, while expectations around availability, maintenance efficiency and onboard experience continue to rise.
DTi device technologies GmbH is addressing these challenges with its Seal-Fast silicone sealing systems and Spring-Fast SL-FST metal substrate grommet edging, designed specifically to meet international fire, smoke and toxicity (FST) requirements while improving installation efficiency and long-term reliability.
Risks of PVC
Conventional solutions such as PVC edge trims and adhesive-based nylon grommets are widely used across rail applications but present well-documented risks. PVC is not compliant with modern FST standards and can emit chlorine-based gases at elevated temperatures. Nylon grommets applied with adhesive are labour intensive to install, degrade over time and can contribute to increased toxic smoke loads during a fire event.
DTi’s Seal-Fast silicone seals are engineered for use in doors, windows, equipment enclosures and exterior housings where protection from heat, smoke, fumes, dust and moisture is critical. Manufactured from high performance silicone and reinforced with steel or stainless steel wire, the seals provide strong edge retention, impact resistance and long service life under vibration and thermal cycling.
The seals are compliant with major international standards including EN 45545-2, NFPA 130, UL94 V-0, UL 50E and relevant ASTM specifications, allowing OEMs to specify a single solution across multiple regions. Low compression set characteristics ensure the seals recover their original shape after repeated door cycles, maintaining smoke and fire integrity over the vehicle lifecycle.
Complementing the sealing systems is DTi’s Spring-Fast SL-FST grommet edging, designed to protect wiring looms and cable runs from abrasion at sharp metal cut-outs. Wiring is a critical safety system in modern rail vehicles, carrying power and data to braking, HVAC, passenger information and entertainment systems. Damage to cable insulation can lead to system failures, electrical arcing or, in the worst case, fire initiation.
Spring-Fast SL-FST uses a steel substrate for permanent edge retention and is encapsulated in a fully FST compliant thermoplastic. Unlike traditional grommets, it requires no adhesive and installs using finger pressure alone. DTi reports that this reduces installation time by at least 49 percent and delivers a 9.5 fold improvement in productivity compared with glued nylon alternatives.
According to DTi, the product has recorded a zero failure rate over more than 30 years of service across rail, defence and industrial applications. The elimination of adhesives also removes a common source of long-term degradation and reduces the toxic contribution of bonded materials in fire scenarios.
Global Rail Applications
Seal-Fast silicone seals are already deployed across multiple international rail programmes, including locomotive engine compartments, door and window systems, power supply enclosures and exterior brake system housings in Europe, North America and Asia.
“Metal reinforcement, FST compliance and silicone material performance are the three fundamentals for safe long-term sealing in rail applications,” says Nick Petri, Managing Director of DTi device technologies. “When any one of those is missing, reliability and fire performance are compromised.”
As regulators and operators place greater emphasis on fire safety engineering and lifecycle risk reduction, components such as sealing gaskets and grommet edging are receiving increased scrutiny. DTi’s Seal-Fast and Spring-Fast SL-FST systems offer rail OEMs a route to improved compliance, reduced installation cost and enhanced operational resilience, while supporting safer passenger environments across global rail networks.
