Why do I find these videos so relaxing? Its good, simple content.

These trains have taller or larger gear to gear ratios or gear parts than class 720s as can be heard from the sound of the motor/gear box drives. But class 720 motors is geared to a higher speed as the synchronous sounds of the motor are deeper at the same speeds if you compare the class 720 and 730 trains side by side sound and acceleration wise

Faster than class 720s for sure