Ken Kozicki from BISCO® Silicones recently authored an article for Railway Technology International about the design considerations that go into creating comfortable railcar seat cushions.  How important are first impressions for seating when a passenger steps into the railcar? Obviously, if it’s the Orient Express or another high end rail system, the feeling of luxury must be present.  But even for standard commuter railcars, seat cushions do make an impression.  Ken notes:

“…the most prevalent and obvious fixture within any interior, rendering, brochure, or maze of booth exhibits is the seat or array of seats. The type of seat will vary from the most outrageously luxurious – slated for a VIP very high speed Oriental Express pod – to the simplest and ergonomic that allows for rows and rows of passengers in a configuration that would be suitable for the rush hour of London, Shanghai or San Paulo….What has taken teams of engineers and designers months, if not years, to conceptualise, design, prototype, test (and re-test), will be given a judgment in less than ten seconds. So from that, one could wonder just how important is the first impression of a railcar seat?”

In this article, Ken look at the design considerations that need to be factored in when choosing the right seat cushion for a railcar:  Ken highlights the following:

  • the number of seating positions per coach (as required by the transit authority)
  • materials’ standards for flame, smoke, and toxicity (FST)
  • type of train service (urban metro system versus suburban commuter), and
  • severity of usage.

Ken also discusses the new concerns of sustainability and end-of-life:

“This is being driven by questions related to the disposal of the seat: “What will become of a worn, damaged, or obsolete seat?” Will it be thrown into a land-fill? What are the decomposition ramifications of that seat in a land-fill?”

All good questions.  But what about the seat itself and the cushioning material? Are some better than others?  Ken suggests yes, there are differences between one cushioning material from another:

“…cushions have differences in profile, appearance and texture, it is not obvious that there are different types of materials used to fabricate the cushions. These materials are usually in the form of foam, such as a filled-polyurethane, silicone, and melamine. The foam which is specified for the fabrication of the cushion will have been tested to the various FST standards, ensuring the safety of the passengers. In addition, some of the foam materials may have been cycletested to simulate wear and usage, which brings us back to our earlier statement of first impressions. Often, seat cushion foam materials are tested and certified to a characteristic known as indention force deflection (IFD).”

2-D & 3-D view of thin profile seat with loaded urethane

“A typical IFD test method will be comprised of a disk of a determined diameter that compresses the foam material a certain percentage of its thickness, and then measures the amount of “pushback” force the foam has. This is its indention force deflection, and is directly related to the comfort of the seat. In production, the foam will be certified according to this test. If it is within the IFD tolerance range, the foam will be qualified for seat cushion fabrication.”

Of course, Ken highlights that the bigger test happens after many months of wear on the cushion, after the “pushback” force has been worn down.  Different materials, like silicone foam, do a better job over the life of a cushion than other materials.

To read Ken’s final recommendations, either view the article here (in a magazine viewer) or download a full PDF of the printed article.

Related Links

BISCO Material Selection Guide

Floating Floor Design Tool

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