3 ms·

Thank you. I didn't know about that requirement; and it would obviously be ridiculous to stipulate that airframes be made heavy.

• jzwinck 11y ago
  Planes are made heavy, for the same reasons as trains: safety enhancement and cost reduction. Ever notice how every wheelie cart on a plane has not one but two locking handles to secure it? How about the ram air turbine [1] which is used almost never but weighs hundreds of pounds? Seat frames are still made mostly of metal, whereas if weight were the only consideration they would probably be carbon fiber. [1] https://en.wikipedia.org/wiki/Ram_air_turbine https://en.wikipedia.org/wiki/Ram_air_turbine
  • etep 11y ago
    Yes, I would not dispute your statement, but that does not contradict the fact that airframe weight is minimized to increase efficiency. I did notice the seats were mostly metal, but I also noticed their (essentially) honeycombed design: they are mostly the rigid frame, rather than solid metal. I'm sure if they could reasonably remove the ram air turbine, they absolutely would (both for cost and efficiency).
• sabj 11y ago
  One reason for these tough requirements is that a very large portion of U.S. passenger rail routes go over track owned (and used) by freight rail companies. Therefore, passenger train collisions and other such risks are weighed not only against other passenger trains, but also heavier freight trains. This is one reason why U.S. trains have (relatively) 'harsher' requirements than other countries where track is not shared to such a high extent. Separately, this degree of track-sharing is one of the reasons why average passenger rail journey speed has decreased in many places over a 100-year time period! Obviously, in both cases, there are many many factors involved - but, an important element.