Legion stands out in the crowd: a British-based company is building a global business in improving mobility in crowded areas by turning people into dots on a computer screen

International Railway Journal, June, 2004 by Mike Knutton

LEGION is a unique software product that simulates the movement of people in crowded places such as sports stadiums and railway interchanges and stations, plus the interface between the two. Its aim, as with all computer modelling, is not to recreate reality but the results of reality so that it can serve as a problem solving tool. It can, [or example, be used to increase capacity, improve performance, contain costs, improve space utilisation, and eliminate unsafe schemes or operational practices.

In the railway context, it has already been used to ensure that the existing Tsim Sha Tsui metro station in Hong Kong will be able to cope with traffic demand forecasts for 2011; to optimise passenger flows in the physically restricted area of the new Hung Horn interchange that will be part of the Kowloon-Canton Railway's Sha Tin-Central link, also in Hong Kong; and assessing passenger boarding and alighting behaviour on the proposed cross-London rail link, Crossrail, to establish whether a precise frequency can he achieved.

Legion is a young company, founded in 1997 by science, technology, and finance entrepreneur, Mr Douglas Connor. The current chief executive, Mr Martin Band, joined from Oracle in 2003. The company licenses its software to clients and also offers consultancy and an implementation package that includes training. Such is the pace of development that Legion releases two new versions of its software each year. Version 2.0, a significantly enhanced pack age, will replace the current Version 1.7 any time now.

"Essentially, Legion is about making dots move about a screen in such a manner that crowds are simulated so that they show the same characteristics as real people," Band told me. "This enables aspects of station de sign to be checked in relation to factors such as the length of queues, density of crowding, interchange time between platforms, and station evacuation time."

As a product, it is not based on lists of rules and assumptions about how people move and behave such as likening them to flows of water or pieces on a chessboard. It is based instead on observation of real people in real situations.

Legion took thousands of hours of video footage, which were digitised and analysed in great detail, and from which more than 4 million measurements were taken. So, although the basis is empirical, simulated passenger's (the dots) behave like the real thing. This has been demonstrated by comparisons between video and simulation that were pretty close, with any variations being within an acceptable range. This is because the simulator algorithm is based on field measurements.

Some smart maths and the injection of a predictive capacity form the bridge between video and software to make a program that is meaningful for railways, stadium operators or anyone else with facilities dealing with large numbers of people.

Dr Kate Hammer, Legion's marketing manager, commented: "The reason that Legion software can provide outputs from simulation that can be used to create the operator's matrix is because the analytic power of the software understands the experience of every individual at every moment in time. That is the kind of regularity that has never been possible before."

There is a decision process going on with the movement of each dot on the screen, and it takes into account factors such as walking speed, people's personal space preferences (Chinese people tend to be more tolerant of heavy crowding than Europeans, for example), and the intensity of crowding.

Legion indicates pinch points and can suggest solutions such as rounding off sharp corners (which tend to slow people down as they move through a station), relocating ticket machines if they restrict passenger flow, reversing escalator direction, adding new gates, and replacing conventional doors with sliding doors.

All these things were highlighted in the Legion study at Tsim Sha Tsui station in Hong Kong. The changes can be implemented at low cost but the effect will double the throughput capacity of the station concourse.

In the Hung Hom application, the site has a small footprint of 12,500[m.sup.2]. The three-way interchange will have to handle more than 130,000 passengers/h and more than 1 million each day malting it one of the world's most ambitious schemes to date. Two lines (East Rail and West Rail) will terminate at the station with the new Sha Tin-Central line continuing through.

The design, by Atkins China, has to cater for passengers interchanging between six platforms, depending on the timetable and passenger origins and destinations. Atkins used the Legion pedestrian simulation software to test the viability and safely of the proposed station design, including testing an initial design Mr peak forecast demand.

The simulation showed that the station would not be able to handle the forecast numbers, even though all design guidelines had been met because imbalanced cross flows caused the failure of the initial layout. An iterative design and simulation process that included identifying pinch points and recommending design alterations produced a re-design that complied with the peak demand forecast, thereby increasing station capacity by 35% without increasing the station footprint--a vital consideration given the price of land in Hong Kong.