One other thought: In times of congestion, it’s not uncommon for tube stations to limit access to prevent overcrowding. I always hate entering a very busy stati

One other thought: In times of congestion, it’s not uncommon for tube stations to limit access to prevent overcrowding. I always hate entering a very busy station (or shopping mall) where both sides of the escalator are completely full, as there’s a big risk of injury when there’s no space at the escalator exit, and you have a pile of people being rammed into one spot. It’s not an issue specific to stand-only escalators, just exacerbated by it. With half the escalator reserved for walking, this issue should happen less. Incidentally in these same overcrowded stations it’s not uncommon for the escalator to be turned off intentionally to prevent such problems. So both sides have to walk!