It’s normal for electric locomotives to make some kind of ‘buzzing’ noise as their accelerate, due to the way that power is applied to their traction motors. But the Siemens EuroSprinter family of electric locomotives make an unexpected sound – a ‘Do Re Mi’ musical scale as they power away from the station.
You can listen to it yourself in this video of a ÖBB Class 1116 ‘Taurus’ locomotive departing Zürich HBF on a Railjet service.
And the freight version of the EuroSprinter also playing a similar tune.
Over on Reddit user ‘alltheacro’ explains the phenomenon.
The source is due to the variable frequency drive. You can’t apply full power to the motors suddenly because it would damage components, and the wheels would spin as well, causing damage to the wheels and track. So the power is switched on and off very quickly at different ratios (duty cycle) and different points on the motor’s rotation. Because there are hundreds of amps at high voltages involved, the magnetic fields are strong and anything carrying current – cables, the coils in the motors, etc), and other metal components near them, vibrate. There is also traction control on each individual bogie (ie set of wheels.) If one starts to slip, the train’s control system throttles it back, but the others can keep going. So we get a chorus of different musical notes.
But that isn’t all the train can do:
The same locomotive has an operator’s panel with Easter eggs for amusing sound effects, playing MIDI files, and a music keyboard mode
Those engineers at Siemens must have a lot of time on their hands. 😛
And another Easter egg
Turns out the Deutsche Bahn ICE3 train can play the German national anthem when placed into service mode.
You will definitely not find that anywhere else: Listen to how the power converters of the ICE3 hum the German national anthem !!! Note: In planning mode, this is not possible, but only with special Siemens software!
Which sounds like: