Vibrations in trains_Anagha Engineers

Railways And Why They Require Sealants

When we talk about applications of sealants, we almost always associate it with the construction or manufacturing industries. But, sealants are used everywhere around us, you just have to know the where and the how. In today’s article, we take a look at how the railways industry uses sealants in their manufacturing process of trains.

What could be the factors that matter for the railways industry? It will be in their best interests to ensure that the trains are safe and comfortable for regular use, while also having a long lifetime. When manufacturing a train that meets these broad criteria, sealants and adhesives play a lesser-known but highly significant role. These products are thus, used regularly for both interior and exterior application. Sealants and adhesives are used in almost all parts of railway manufacturing, from design to production to maintenance, be it for high-speed trains to light rail transit.

Railways_Anagha Engineers
To hold the bodies of the trains together, very few materials work as well as sealants

The uses of sealants and adhesives in railway vehicles

One of the most easily spotted applications  is for the joints between floors and walls. Door and window frame fixing is yet another application. This application is because these sealants and adhesives bond strongly with glass, metal and plastics. The products used are categorised into:

  • Sealants
  • Adhesive sealants
  • Adhesives. 

New to this categorisation, adhesive sealants offer many desirable properties. 

Additionally, they are also rigorously used to seal and protect joints, over laps and seams. Due to the rough conditions trains go through every day, they also develop holes and cracks in them. Sealants can be used for repair works here. 

Adhesives are required to bond together the interior and exterior panels and hold them in place. They are needed because they are infinitely better than traditional fasteners. There are also specialised adhesives used for bonding together the seal upholstery.

The requirements of sealants and adhesives for railways

Since railways are the heavy-duty modes of public transport, railway vehicles are always subject to the harsh weather conditions and vibrations. Thus, it becomes essential to the frequently used sealants and adhesives to have the following properties:

  • Shock resistance: A train is subject to continuous vibrations when in use. Thus the sealant/ adhesive should have the capability to withstand extended periods of heavy vibrations. 
  • Electrically insulation: Electric insulation is a significant property required for a sealant or adhesive that is to be applicable in railway vehicles. 
  • Weather-resistance: Because of the continuous exposure to the sun, UV radiation, rain and other weather conditions, it is desirable to have sealants used which show firm resistance to these ever-changing conditions.  
  • Visual appeal: Being a fundamental mode of public transport, the visual appeal that the vehicle should have on the passenger should not go unnoticed. In most cases, sealants and adhesives form smooth, finished surfaces which are also paintable.
  • Time and cost-efficient: Since trains are heavily used across the country by millions of people every day, it becomes essential that these solutions are active within the shortest possible time.
  • Contributing to safety:  Sealants that are certified and can match up to industrial safety standards should always be selected. This particular point is always stressed upon because every application becomes critical at some point in its life. 
Railways_Vibrations absorber_Anagha Engineers
Because of the high vibrations, devices that harvest this energy from the railways have been pioneered.

How adhesives and sealants compare to alternatives

There is no need for a question about why sealants and adhesives are better than other options. Being lighter in weight and offering greater adhesive strength is simply one of the advantages. We have listed some of the benefits of sealants and why they should be preferred: 

  • Strength: Despite being flexible and immune to hazards, sealants show a much higher adhesive strength than welded bonds or fasteners.
  • Eco-friendliness: Sealants and adhesives of today strive to be eco-friendly. They are formulated in such a way they contain no isocyanate, silicone, halogens or solvents.
  • Application: When you compare using alternatives like welding, it is not possible to carry it out by yourself. You require professionals who are skilled in the process of welding materials together. But when you are using a sealant or adhesive, it comes in spray cans through which application becomes easy, even for home users. Furthermore, these sealants can be applied using a brush, spray, spreading, web coating, beads, wheel or dots.
  • Durability: sealants and adhesives do not corrode easily under harsh climatic conditions. Thus, it makes them more suitable than other alternatives like traditional fasteners and welded bonds.
Vibrations in trains_Anagha Engineers
Sealants and adhesives improve the life of a train our railways drastically.

Certification of sealants and adhesives for Railways

There are international organisations that are given the role of testing materials and making sure that all products that enter the market are safe for their particular application. When most of our daily lives depend on sealants in one form or the other, it becomes imperative to have checks and standards in place. Therefore, to guarantee safety and compliance with regulations, you need to make sure that the product has a certificate mentioning one or more of these following standards:

  • EN 45545 – 2:  The latest European standard for the fire testing of sealants in rail transport. The adhesives are categorised into sets R22 and R23 which show requirements for inductance coils, interior seals, regular coils and contacts. The products undergo assessment for three hazard levels with an increasing level of requirements for each. The lowest is HL1, and the highest is HL3. It is necessary that bonds and seals have to comply with all three hazards levels to guarantee the safety of passengers and staff in the event of an onboard fire.
  • FMVSS 212 stands for Federal Motor Vehicle Safety Standard. This is a test to check if the sealant is compatible with the process of windshield mounting. It follows the procedure of assessing the strength and durability of the windshield (and window) mounting in a test-crash situation. 
  • DNV GL is a standard to keep a check on functional safety for the rail industry. They conduct and compile many European and international standards to check for reliability, availability, maintainability and safety, software and system safety. 
  • WheelMark is a certification provided to sealants that can withstand harsh environments for extended periods of time. This standard is also used for sealants using in the shipbuilding industry as well.
  • SEGA: The SEGA standard assures that the sealants that receive its certification are harmless for use in the food preservation and transportation industry. Because contamination is a significant concern, this certification, together with HACCP, is vital to attain for the sealant manufacturers. 


While this may seem a little too technical, it is important to know how sealants and adhesives affect your life. If you want to know more, click the button below to give us a call.

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