[belugacat]

In the case of the interface shown in the train video, the key thing the operator will rely on is the fixed physical position of the controls first, then their shape, dimension, and color.

The icons really aren’t going to matter as much. And I’d argue they’d probably be better off replaced by text labels. Imagine a new operator in a stressful situation being guided eg on the phone - how would you describe to them which of the 2 buttons with a center arrow with a curve to their right they should press, for the control panel at 4:31? You’ll end up saying “the center left/right button”, or “the one above the green P button” because those icons are pretty hard to distinguish.

Swap the icons between 2 controls one day, and watch even the most skilled operator make mistakes.