Metro escalator

When I got off the metro at Haymarket and saw that the middle escalator was switched off, I was annoyed, because it’s not that long since they took the staircase away to make it *into* an escalator. And it seemed all a bit ridiculous to do all that work and then take it away.

But when I actually read the sign, it does seem quite sensible. It’s there when it’s needed (morning and evening rush hours) and switched off during the day when it’s quieter to save energy. Seems to make sense.