Siemens Eurospinter "Taurus" Compilation - "Do Re Mi" music locomotive

EuroSprinter family of electric locomotives make an unexpected sound - a ‘Do Re Mi’ musical scale as they power away from the station.
This 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.

[@Metaintelligencia]

Do
Re
Me
Fa
So
La
Ti
DAHHHHHHHHHHHHHHHHHHHHHH