Why Do High Speed Trains Have Those Sharp Noses?

Discussion in 'TSW General Discussion' started by geloxo, Nov 10, 2020.

  1. geloxo

    geloxo Well-Known Member

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    There are several reasons. First one is to be able to pass the crash tests. Yes, as project can be nice, but if it fails the test it will never come into service :D More important are the aerodynamics, as the more efficient the shape is the less power consumption and the higher speeds are possible. But on top of that is a problem that may not be known by everybody: the sonic boom in the tunnels.

    When train enters a tunnel at high speed it compresses the air ahead, and as it can´t escape through the sides it produces a sonic boom like the combat jets do, even if trains are subsonic vehicles. That can be heard at the other side of the tunnel and it´s an amazing effect.

    This can be disturbing for local citizens and animals, but there´s a real danger if this happens in a valley area, due to the echo that could produced if trains where not designed to reduce the strenght of effect with their nose. With those noses the amount of compressed air left in front of them is much smaller but even if it´s reduced they still produce a sonic boom and it can damage structures near the tunnel exists, both by the sonic boom itself and by the airflow left after it and after the train passage, so normally no vital equipment is placed there, and if done, it shall always be protected.

    This video shows the effect in action when the second ICE train enters the tunnel:



    So far I was not able to reproduce that in game hahahaha. Dovetail, please note it down for our whishlist, as part of the reverb sound fix for tunnels :D

    Cheers
     
    Last edited: Nov 10, 2020
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  2. tallboy7648

    tallboy7648 Well-Known Member

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    I think a sonic boom would be cool
     
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  3. geloxo

    geloxo Well-Known Member

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    Well despite being cool or not it happens to real trains, so this is something relevant to consider for the simulation. In the video you can notice a small explosion and then the sound of the air approaching before train reaches the exit. And it´s a quite long tunnel as train takes a time to exit...

    Cheers
     
    Last edited: Nov 10, 2020
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  4. tallboy7648

    tallboy7648 Well-Known Member

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    Yes and I think for a simulation, this needs to be added in
     
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  5. ex-railwayman

    ex-railwayman Active Member

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    I don't think you'll achieve a sonic boom on the West Somerset route somehow!!!! :D

    Cheerz. Steve.
     
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  6. geloxo

    geloxo Well-Known Member

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    Yes, it will be definitely quite hard hahaha :D. Anyway we need the tunnels also in areas where you drive at top speeds, so not all high speed routes may be suitable for that.

    Cheers
     
  7. stujoy

    stujoy Well-Known Member

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    I’ve never heard of that phenomenon before. It’s quite dramatic. You can’t really tell from the video how loud it is though, I’m guessing if you were close enough to the tunnel you’d feel it too. I’m not sure it would ever make it into TSW, although it would be good.
     
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  8. geloxo

    geloxo Well-Known Member

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    It depends on the tunnel and the train. In this case in a spanish line with an AVE train it´s quite impressive. And camera was quite far away from the exits. See it at 1:20 in this video:



    See it at 0:42 in another video of the same place. Not so loud as first one:



    In the first video you can see that there´s another tunnel just after the first one and train does not produce the sound when entering it. The effect is only affecting the exit, as air is pushed in the train direction.

    Cheers
     
    Last edited: Nov 11, 2020
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  9. stujoy

    stujoy Well-Known Member

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    That’s incredible.
     
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  10. tallboy7648

    tallboy7648 Well-Known Member

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    They do need to improve audio in this game such as track noise
     
  11. 7orenz

    7orenz Well-Known Member

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    From this video we can learn two new things:

    1) the sonic boom produced by the air at the exit of tunnels and amplified by the echo effect.

    2) German trains couches are not only double deckers (dopplestock cars) like in TSW :D
     
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