I suddenly want to buy the complete collection of Train Simulator on Steam
the big train that hopefully could
If anyone is wondering for the technical reason behind that sound, the train wheels are experiencing some slip and running at slightly different RPM each. The way this trains inverter works results in those differences in RPM producing different sound pitches (and also this train generally has weird sound, just usually not polyphonic like on this video)
Wow why did they choose frequencies in the key of C major? The engineers must be musical.
[QUOTE=Solid_Granite;51843482]Wow why did they choose frequencies in the key of C major? The engineers must be musical.[/QUOTE]
Hate to be that guy (no fun zone, blah blah) but this has to be [DEL]either fake or[/DEL]a totally intentional feature of the train NOT produced by a natural phenomena or vibrations hitting a resonant frequency coincidentally.
There is simply no way it could hit the sequence of notes it does with the nearly perfect pitch that it does, and then suddenly become polyphonic and play reasonable sounding chords.
[QUOTE=Solid_Granite;51843482]Wow why did they choose frequencies in the key of C major? The engineers must be musical.[/QUOTE]
The train moves because magnetic field is rotating in the engine and pulls the rotor to rotate as well. The frequency at which the field must rotate depends on a ton of things, but usually ends up between 0 Hz and ~100-200 Hz.
The motor must be driven by a sine wave of that frequency. But producing a since wave like that is hard when you have hundreds of amperes of high voltage power running through. So the power is switched on and off about 200 to 600 times per second to simulate a sine wave.
E.g. by keeping stuff on for longer, it simulates higher voltage, keeping stuff off for longer simulates lower voltage of the sine wave:
[IMG]http://www.vanatoo.com/uploads/images/class-d.jpg[/IMG]
Since the resulting sine wave must go from 0 Hz to ~100-200 Hz and due to transistors having finite switching speeds the switching numbers must be limited, what happens is that the pulse width is adjusted. So transistors will be switching at a certain rate, then pulse width is adjusted to bring the rate back into acceptable bounds. For Taurus they picked frequencies with some sort of power of two scale, giving a musical-like sound.
It's probably mostly a coincidence given how different factors come into play.
That title is magical.
[QUOTE=Socram;51843555]Hate to be that guy (no fun zone, blah blah) but this has to be either fake or a totally intentional feature of the train NOT produced by a natural phenomena or vibrations hitting a resonant frequency.
There is simply no way it could hit the sequence of notes it does with the nearly perfect pitch that it does, and then suddenly become polyphonic and play reasonable sounding chords.[/QUOTE]
It can hit a sequence of notes if the PWM is switched in a way that produces power of two related step in number of pulses per second. The choice of how it goes through number of pulses per second to approximate a sine wave is largely arbitrary and Taurus train is known to have this specific melodic sequence.
Polyphony appears because the train is pulling a lot of wagons and the wheels start slipping, the anti-slipping system engages and keeps varying the wheel rotation rates within a certain margin. The video is a case of "being lucky to be in a right place at a right time, with a right train"
See this for how the train startup sounds like with no slip involved (and therefore no polyphony):
[media]https://www.youtube.com/watch?v=-SDYdHzT7Qw[/media]
reminds me of this
[media]https://www.youtube.com/watch?v=MIgMeyW4TEM[/media]
[QUOTE=BlackPhoenix;51843567]See this for how the train startup sounds like with no slip involved (and therefore no polyphony)[/media][/QUOTE]
Thanks for the additional video source, I have tweaked my post slightly. I don't think it is a fake/edit anymore, but there is no denying that this was done intentionally by the engineers. PWM doesn't correspond so perfectly to musical frequencies accidentally like that.
Almost every time I waited on the East Train Station in Munich, one of these things stopped and started.
The thing ALWAYS makes these sounds when accelerating, no matter which weather or how many wagons.
[url]https://de.wikipedia.org/wiki/Siemens_ES64U2#Ger.C3.A4uschentwicklung[/url]
(german source on why it's making those sounds)
Absolutely lovely, I wish I could translate it but I don't even understand half of it in german.
Here is a cute compilation from Austria
[media]https://www.youtube.com/watch?v=tEjaPYjjjtM[/media]
Oh please
[video=youtube;sFNSyH9mpP4]https://www.youtube.com/watch?v=sFNSyH9mpP4[/video]
Same maker of control devices (Siemens). As far as I know this is the only rail company in Japan right now with trains that have inverter control devices by a foreign company. The devices on some trains are getting replaced lately though because they have been slightly unreliable in comparison to those by Japanese manufacturers, some have even failed already (just under 20 years) which is early in comparison to Japanese ones which can last probably at least another 10 years.
[QUOTE=daigennki;51844266] The devices on some trains are getting replaced lately though because they have been slightly unreliable in comparison to those by Japanese manufacturers.[/QUOTE]
Was? German engineering never fails! Schweinehund!
[sp]Not teaming up with you guys anymore.[/sp]
[QUOTE=DMGaina;51844270]Was? German engineering never fails! Schweinehund!
[sp]Not teaming up with you guys anymore.[/sp][/QUOTE]
Sorry, we are starting to miss the melody too. :frown:
I remember reading somewhere that Siemens devices were not fit for Japan's somewhat more humid climate though, I do not know if it has to do with the operating humidity of the devices themselves or the way the devices deal with slipping/loss of friction.
AFAIK this was engineered intentionally, but I think they removed it in a later revision.
[editline]19th February 2017[/editline]
Basically Siemens built an easter egg and then marketed it? :v:
[QUOTE=SEKCobra;51844278]AFAIK this was engineered intentionally, but I think they removed it in a later revision.
[editline]19th February 2017[/editline]
Basically Siemens built an easter egg and then marketed it? :v:[/QUOTE]
Yeah, from what I know an engineer at Siemens decided to throw it in there just for fun, haha :v:
[video]https://youtu.be/GRXlae5casc[/video]
[QUOTE=BlackPhoenix;51843567]
[media]https://www.youtube.com/watch?v=-SDYdHzT7Qw[/media][/QUOTE]
Huh.
[media]https://www.youtube.com/watch?v=YxBcH1HYsuI[/media]
I knew it sounded familiar.
sounds like some piece of music from blade runner
So when will we be seeing one of these things put on a rolling road and used to actually play music?
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