Platform screen doors gain in popularity: more and more metros are installing platform screen doors at stations to improve safety, speed boarding, reduce air-conditioning costs, and improve the station environment

International Railway Journal, June, 2004

THE demand for platform screen door systems around the world has seen dramatic growth in recent years. Westinghouse Platform Screen Doors, which is part of the Knorr-Bremse Group, has recently been awarded contracts for its platform screen door system for the Paris and Toulouse metros. The French contracts are the latest in a series of major contracts which has seen the company's platform screen systems installed in China, Malaysia, Singapore, Denmark, and Britain.

Platform screen doors fitted to metro station platforms form a barrier between passengers and the track and train. The doors are opened automatically by sophisticated interface control electronics which communicate between the approaching Wain, the signalling, and systems within the door architecture. The train control system ensures that the train stops in the correct position. The opening of the doors on the train and platform is controlled from the train to ensure that both sets of doors open simultaneously. When passengers are safely on board the train, the doors are closed in precise harmony with those on the platform.

This barrier provides a number of important benefits to both passengers and operators. Safety is of course the main benefit for passengers, as the doors prevent access to the track. In addition, doors make the platform environment cleaner and quieter. Platforms fitted with full-height platform screen doors can be climate controlled which is especially beneficial in hot and humid climates.

The point has now been reached where metro station architects and designers are incorporating and indeed embracing platform screen doors into their designs. Platform screen doors, typically with a glass and stainless steel or aluminium finish, are individually designed rather than being standard items which the station design has to accommodate. Now that the platform is protected from the track, station designers feel more confident about using materials that would have been ruled out before because they would have been quickly damaged or defaced by grime and dirt. As a result, dull concrete is out and shiny marble and specially commissioned original works of arts are in. This allows the creation of some quite stunning architecture below ground.

There are also major benefits for operators in fitting platform screen doors. The automation and safety benefits that fire platform screen door system brings to the dynamics of moving large numbers of people on and off trains are considerable. Platform screen doors can reduce boarding times at stations because passengers know exactly where to stand on the platform. This can improve scheduling efficiency and allow shorter headways.

Platform screen doors can reduce air-conditioning and ventilation costs for operators by isolating the platforms from the train, track, and tunnels. It has been demonstrated in many cases that savings on the costs of air-conditioning alone can cover the cost of the installation of the platform screen doors. There is the potential for costs to be recovered, typically within three to four years. The train driver can approach a station at a higher speed in total confidence, secure in the knowledge that the line ahead is clear.

Full-height platform screen doors are usually fitted to new metros and in many cases can be fitted to existing metro platforms. Where an existing metro has been designed so that the movement of the train forms a key part of the ventilation system, platform edge doors can be fitted instead. These are similar to full-height platform screen doors, but leave a gap at the top to allow the ventilation system to function as it was designed to do. Platform edge doors must be designed to withstand the pressure and vacuum forces of the airflow on the platform. They have all the safety benefits for passengers, reduce noise and dust, but do not allow for climatic control of the platform.

Platform screen gates are also becoming more popular. These are half height gates that are generally used on above-ground metro stations where their function is solely to improve safety.

"Platform screen doors are now a crucial and fully-integrated part of the modern metro platform fabric," commented Mr Paul Johnson, managing director of Westinghouse Platform Screen Doors. "The platform screen door system synchronisation must possess integrity, endurance, and reliability so that it can be fully trusted by the passenger and operator alike.

"We have built our international reputation on three main core values," Johnson continued. "First, we deliver what we promise with systems installed oil time and to budget. We do this by working closely with the operators, designers, and builders of the metro. Secondly, we have audited a staggering 40 million successful door opening and closing cycles on our system projects to date. Thirdly, we work closely with our customers to create a product which is aesthetically correct for their particular project. We want our doors to contribute to the overall appearance and ambience of the platform environment." It appears that platform screen doors are the way forward for modern metros. The growth in demand seems set to continue as does the demand for installing platform edge gates on existing metro platforms. Key markets that are expected to show the greatest demand are China and the Far East. Westinghouse has recently teamed up with the Guangzhou Guangri Group in China to bid jointly for the design, manufacture, installation, and maintenance of platform screen door systems in China.