<P> There are often loudspeakers as part of a public address (PA) system . The PA system is often used where dynamic timetables or electronic displays are not present . A variety of information is presented, including destinations and times (for all trains, or only the more important long - distance trains), delays, cancellations, platform changes, changes in routes and destinations, the number of carriages in the train and the location of first class or luggage compartments, and supplementary fee or reservation requirements . </P> <P> Some metro stations have platform screen doors between the platforms and the tracks . They provide more safety, and they allow the heating or air conditioning in the station to be separated from the ventilation in the tunnel, thus being more efficient and effective . They have been installed in most stations of the Singapore MRT and the Hong Kong MTR, and stations on the Jubilee Line Extension in London . </P> <P> Platforms should be sloped upwards slightly towards the platform edge to prevent wheeled objects such as trolleys, prams and wheelchairs from rolling away and into the path of the train . Many platforms have a cavity underneath an overhanging edge so that people who may fall off the platform can seek shelter from incoming trains . A dangerous practice is sitting on the edge of the platform, which requires withdrawing the legs fast enough when a train arrives . </P> <P> In high - speed rail, passing trains are a significant safety problem as the safe distance from the platform edge increases with the speed of the passing train . A study done by the United States Department of Transportation in 1999 found that trains passing station platforms at speeds of 240 kilometres per hour (150 mph) can pose safety concerns to passengers on the platforms who are 2 metres (6.6 ft) away from the edge due to the aerodynamic effects created by pressure and induced airflow with speeds of 64 kilometres per hour (40 mph) to 95 kilometres per hour (59 mph) depending on the train body aerodynamic designs . Additionally, the airflow can cause debris to be blown out to the waiting passengers . If the passengers stand closer at 1 metre (3.3 ft), the risk increases with airflow that can reach speeds of 79 kilometres per hour (49 mph) to 116 kilometres per hour (72 mph). </P>

Rules to be followed on railway station platform