b) Crowds usually build-up at the platforms, in front of the AFC gate lines / ticketing
machines, passageways, footbridge, escalator landings, staircases, entrances, and so on.
c) Crowd safety limits can be expressed as the maximum number of passenger within a
particular area of a station at any one time which can be measured by the maximum
queuing or waiting time of the passengers at the particular point of the station.