Do you recognise this tune?
It is the scale performed by certain ÖBB trains upon taking off.
Surely you are wondering and dying to find out…
What is the key of this scale?
By some miracle or extremely careful engineering, the tune conforms perfectly to the tonal system of Western music that seperates an octave in 12 equal tones (which we call half-tones). Furthermore, it incorporates whole and half steps at just the right positions to form a diatonic scale which also happens to avoid sharps and flats. I.e. you can play it on the piano using only white keys. I marked the half-tone steps here:
(The last tone gets somewhat higher – no more than a quarter-tone – as the train accelerates, but goes back down again – at least from the point of view of someone who watches the train leave from the platform – which can probably be attributed to the Doppler effect.)
We can’t really declare the key as C major or a minor just because there are no sharps and flats, as neither C nor A hold a priviledged position on this scale. It also seems that several versions exist, starting the scale on different tones, so that does not help either to find the key tone of this scale. However, because every version ends on D, we shall take the ending note as the point of reference. And thus the train scale is played in the modern D Dorian mode.
You can download the official version on the ÖBB blog.
P.S.: An example of a variation I heard yesterday: