Sealants and adhesives for safety and comfort on railways
Safety, comfort and durability are key factors in manufacturing railway vehicles such as trains, trams and underground trains. Among other materials, adhesives and sealants play a crucial role in the production process and finished product. Sealants and adhesives for rail transport are used in the interiors and exteriors of rail vehicles throughout their lifecycle from design and production to field service and maintenance. These products can be used for sealing and bonding all railway vehicles from high speed trains to light rail transit.
The main task of sealants and adhesives is to make the manufacturing process faster and the vehicles safer.The wished results can be obtained with for example MS polymers, contact adhesives and 2K polyurethanes depending on the application.
The uses of sealants and adhesives in railway vehicles
Adhesives and sealants bond and seal plastics, glass and metal in railway vehicles such as trains and trams. The products can roughly be divided into sealants, adhesive sealants and adhesives. The adhesive sealants are the newest addition, and include products with superior sealing and light adhesive properties.
Sealants and adhesive sealants are most convenient in sealing and bonding windows and doors as well as floors and roof panels. Additionally they seal and protect joints, overlaps and seams as well as fill gaps and cracks in repair applications.
Adhesives, for their part, bond both interior and exterior panels to each other and hold them on their places. Additionally they bond profiles and frames, and so replace traditional fasteners.
The requirements of sealants and adhesives for rail transport
Trains, trams and underground trains are subject to harsh environments created by changing weather conditions, vibration and continuous use. Therefore, sealants and adhesives for rail transport must meet the requirements set by the environment; they must be:
- Shock resistant: as the travel on the rails together with the track switches may cause vibration, it is of high importance that the bonds and seals do not break. Therefore, they must be strong and flexible.
- Electrically insulating: for some applications, it is paramount in regards of safety that the adhesives and sealants do not conduct electricity or that they completely insulate electrical charge.
- Weather resistant: especially adhesives and sealants for exterior materials need to be weather resistant: they must endure temperature fluctuation, rain and UV radiation without being affected. Flexibility, UV stability and water resistance are characteristics to choose for.
- Visually appealing: trains, trams and underground trains serve as means for public transportation meaning that the visual aspects must not be ignored. Fortunately, most adhesives and sealants form a neat, equal surface which can even be over coated in order to alter the aesthetics. These adhesives and sealants are also applied to other public transport vehicles such as buses.
- Time and cost efficient: rail vehicles act as an irreplaceable part of the transportation business, and in business time is money. Therefore, the application of adhesives and sealants should be fast, yet it should lead to a highly durable result which does not require frequent maintenance or repairs.
- Contributing to safety: depending on the application, there are sealants and adhesives that are certified and tested for example for fire safety, crash situations, durability in harsh environments and sustainability. The certificates are taken a closer look at later on in this article.
How adhesives and sealants compare to alternatives
The great advantage of sealants and adhesives is that they tend to be lighter in weight and greater in strength compared to their alternatives such as welded bonds. However, high quality adhesives and sealants beat the alternatives also in other measures.
- Strength: compared to welded bonds and fasteners, adhesives and sealants are less likely to break due to their flexibility and immunity to hazards such as corrosion.
- Eco-friendliness: even though sealants and adhesives are chemicals, there are also environmentally friendly solutions that do not contain isocyanate, silicone, halogens or solvents.
- Application: compared to for example welding, the application of adhesives and sealants is by far not as laborious. The application possibilities are also broader: bonds and seals can be created by brush, spray, spreading, wheel, web coating, beads and dots as well as other functional methods.
- Visual appeal: most sealant and adhesive products are available in various colors and if not, they can often be over coated to match the wished visual end result.
- Durability: sealants and adhesives are not affected by corrosion, hence they last longer in harsh environments than traditional fasteners and welded bonds.
Certification of sealants and adhesives for rail Transport
Wherever safety is the priority, certificates and standards play an important role. This is true also for the rail transports and manufacture of railway vehicles. Therefore, to guarantee safety and compliance with regulations, choose for products that have the certificates relevant for your application. Below you can find some of these regarding sealants and adhesives in rail transport.
- EN 45545 – 2 is the newest European standard for fire testing in rail transport. The adhesives and sealants fall under requirement sets R22 and R23 that cover requirements for interior seals, inductance coils, coils and contacts. The standard assesses products for three hazard levels, the lowest requirements being HL1 and the highest HL3. Bonds and seals can be made to comply with all three hazards levels: HL1, HL2 and HL3 to guarantee the safety of passengers and staff during onboard fire.
- FMVSS 212 stands for Federal Motor Vehicle Safety Standard: windshield mounting. This standard assesses the strength and durability of windshield (and window) mounting in crash situation. As the train windshields and windows are often glued and sealed using sealants and adhesives, their behavior in such situations is tested.
- DNV GL provides functional safety for rail industry. DNV GL is a certification body that assesses, among others, products for rail transport according to several European and international standards. For rail transport these include reliability, availability, maintainability and safety, software and system safety. DNV GL certified sealants and adhesives are thus up to standards.
- WheelMark indicates durability in harsh environments. Some adhesive and sealant products for rail transport can be certified according to the Maritime Equipment Directive set by the EU, due to the fact that similar or same products are durable enough to be used in ship building and repair, as well.
- ISEGA assures that products are safe to be used in the preparation, processing, treatment, packing, transport and distribution of food. These products must have the lowest risk of contamination, and other hazards. Therefore, the ISEGA certification, together with HACCP, is crucial especially for sealing and bonding products used in railway vehicles that transport food.
Sealants and adhesives for rail transport are one click away
In case your project is in need of a suitable sealants and adhesives for rail transport, please contact us. Our specialists will assist you in finding the right adhesive or sealant for the specific purpose. By contacting us you can also enquire for more information on the possibilities, assistance in application as well as adhesive and sealant training. Our experts are happy to help.