My guess is that there is no up escalator available and there is insufficient capacity on the station without it. The line is currently open southbound so there is obviously access available to the trains, possibly via stairs.
The essential things in life are seen not with the eyes, but with the heart. --Antoine de St. Exupery
last time I was there only one escalator was available with work on the other.
people had to walk down.
sounds like the remaining one has failed.
Yep, that's the case but repairs on the 'open' escalator were completed a couple of months ago so clearly it didn't go to plan. Without either escalator there's only the narrow staircase and you can't run the station at rush hour with that.
Escalator 1 failed and couldn't be reset. Low step alarm was detected. Supervisor closed station as regulations dictate. Senior Operating official, who is a senior manager and who can suspend the rule book if need be, gave instruction that the station was to be reopened for entry only. Some of the staff went to Blackhorse Road to assist with detrainments.