A platform display , display destination or describer Train (British English) is supplementing the destination sign is arriving train passengers annually giving advance information. Historically they did not even show the next destination and sometimes the type of train. In later usage They Were Replaced by passenger information display systems (PIDS) Allowing for real-time passenger information.
The first railway stations had only a table for passenger information. The train station would be a good option . They were supervised by a station manager who would handle the security requirements for each departing train. The hotel is located in the center of the city, close to the train station and the train station. Different directions would then be called out on the platform. At the time that trains grew into mass transport systems this was not enough anymore. The landing gear has been designed to allow the user to adjust the position of the loudspeaker.
A train describer is originally an additional apparatus at British Railways which ensures that the identity of each train is displayed on the signalbox panel together with the indication of that train’s presence, usually offering routing information.  This routing information would then be passed through to the platform display for passenger information. Technically the train reporting number was pushed from one signal box to the next. A series of interconnected signal boxes and a train describer system (TDS).
In a centralized electronic interlocking the current train hire and identification is used to predict the arrival at the next stop allowing for countdown clocks for passenger information. The term passenger information display has the ability to display a wide variety of information, Which all get their information from a central electronic railway control system. Additionally passenger information displays are used for bus and tram stops.
- Jump up^ https://www.safety.networkrail.co.uk/Services/Jargon-Buster/T/TP-TT/Train-describer
- Jump up^ http://www.davros.org/rail/photos/p009.html