Electronics Review Vol 23 No. 3 - ST Electronics

P R O J E C T SRetrofitting platform screen doors:challenges and solutionsby Ramaswamy Muthuraman, Transport Business Unit, Large-Scale Systems Group, ST ElectronicsTo enhance passenger safety andimprove train headways, many massrapid transit (MRT) operators aroundthe world have started equippingtheir stations with platform screendoors (PSD) at the platform edges.PSD systems enhance passengersafety by preventing commuters fromfalling onto the tracks accidentally incrowded MRT stations. Having PSDhelps organise and direct passengertraffic flow, resulting in shortertrain stoppage time at stations. Thiswill increase train headways aswell. Many governments and MRToperators recognise the benefits ofPSD systems and they now includethis as an integral part of new MRTdevelopments. At the same time,MRT operators have also started toretrofit existing stations with PSDsystems.Others:ECS, UPS,Operator其 他 : 环 控 ,不 间 断 电 源 ,营 运 商SCADA综 合 监 控Track Work轨 道Civil &Structure土 建 与 结 构PSDSystemPSD 系 统RollingStock列 车Grounding& TouchVoltage接 地 与 接 触电 压Figure 1: PSD Interfaces 图 1:PSD 接 口Signalling信 号PowerSupply供 电Unlike new station installations,retrofitting a PSD systems in existingstations poses many challenges andrequires wider disciplinary expertisefrom the PSD system providers. Forexample, during the retrofittingperiod, the MRT station mustremain operational without causingdisruptions to regular train servicesand inconvenience to the commuters.PSD system providers have to committo meet tight project schedules, butare restricted to carrying out most ofthe site work during a short window oftime each day. This requires meticulousplanning and precision execution.Apart from PSD system knowledge andits interfaces with various systems,they need to possess expertise andknowledge in the areas of structuralengineering, air-conditioning and powersupply, to name a few.System InterfacesThe PSD installation must interfacewith many other systems (figure 1). ThePSD systems are relatively heavy andtransfer significant amount of load tothe platform structure. It consumeselectricity even when in a standby mode,and would require communication withthe signalling system to function.To retrofit an MRT station with a PSDsystem, the MRT operator has toenhance all the interfaces so that thesystem can operate seamlessly. Toachieve this, it may be necessary toengage the provider of each system toget the PSD system properly installed.However, cost considerations may notallow the MRT operators to do so. Insuch cases, operators may package thecomplete scope into the PSD systeminstallation contract. Thus, PSD systemproviders must possess the necessaryknowledge and capability to enhance allthe associated system interfaces so thatthe PSD system operates seamlessly.Civil and Structural InterfacesThe PSD system consists primarilyof the bi-parting automatic slidingdoors, as well as fixed screen panelsto be installed at the platform edges,platform-end return doors to access thetracks, and the PSD central controller(PSCC) to be installed at the PSD controlroom. To successfully install a PSDsystem, the system provider requires:• adequate space and strong platformedges for the added load of the PSDsystem;• space and routes for running thepower and control cables betweenthe screen doors, the PSCC, the10 ELECTRONICS REVIEW