I would estimate that there are only 3 escalators operating as often as there are all 4, and there have been quite a few times when only two have been in service.
With the likely growth in passenger numbers in the future, I'm sure this will cause some serious problems if nor improved. Does anyone know what the problem is and when we are likely to see an improvement.
While they are longer than typical railway station escalators, there are plenty of examples of longer escalators. See links