Displays in public transportation perform several functions. Smaller models are present in the vehicles themselves, e.g., in ticket validators. Large-format variants are visible at most railway stations and bus stops. All of them, though, are used to inform passengers about route details, current weather conditions, or – most importantly – departure and arrival times, as well as possible schedule changes.
The screens used at crucial points in the public transport infrastructure play a specific role. They function as a collective grey eminence in the urban space. The displays have a significant impact on the everyday decisions of passengers, yet are so deeply rooted in their minds that are almost imperceptible at the same time. All this, provided that they work properly and are accordingly selected for the very place of their installation.
Standards and requirements
The standards for displays used in the transportation industry differ from those for other applications. Depending on the final location of a given module – the bus interior itself, the space belonging to a tram stop, or a train station – it is certain that it will have to meet some additional requirements, usually officially defined. In the case of displays installed e.g., in trains, the EN 50155: 2018-01 specifies the operating temperature range of devices, their resistance to vibrations, and the permissible intensity of electromagnetic interferences emitted, which may affect the operation of other equipment in the vehicle.
Freedom of shapes
The readability of information is crucial for people using public transport. The installation space in which LCDs are located is often limited in size and does not correspond to the proportions and dimensions of the standard displays. There is no guarantee that typical solutions will be optimal in such applications. Thanks to the development of TFT glass cutting technology, manufacturers can now produce displays in the shape of a circle, square, or even non-standard, excessively stretched rectangle. Such modules are rarely used to display only advertising content. Still, they are ideally suited for showing e.g., the course of the metro, trains, or buses.
Displays selected for transport applications must not restrict passengers’ access to information. Therefore, it is worth paying attention to the full viewing angles (89°/89°/89°/89°), appropriate screen brightness (at least 700 cd/m2, optimally between 1000 cd/m2 and 2500 cd/m2), uniformity of backlight, and high contrast. All these factors guarantee good readability of the presented content, even in direct sunlight.
However, the parameters responsible for readability will not matter at all if the LCD itself… is not working correctly. It would be hard to imagine a train station where screens showing the exact times of departure, arrival, and possible delays of individual trains would be turned off for an hour or two during the day. Due to the need to operate 24/7, transport displays have a mean time between failure (MTBF) of at least 70,000 operating hours. Thanks to this solution, they are perfect for applications requiring an all-day operation. Due to the optimized backlight system, they are distinguished by a lower level of electromagnetic disturbances and low energy consumption. Unisystem’s offer includes models capable of failure-free operation of up to 100,000 hours, which means that the given device will operate properly, without performance loss, for over 10 years.
A popular display in transport applications is, for example, the 46-inch P460HVN05.0 from AUO. This is a standard size used in information kiosks or passenger service points. For instance, several solutions from Litemax like SSF3700-Y with a brightness of 2500 cd/m2, or SSH3805-I with increased LED lifetime will also work well in mass transit. All of them are available in the Unisystem’s offer.
E-paper – a different solution
E-paper displays can be an alternative to LCDs used as timetables or information boards. They have unique properties, like excellent readability in full sunlight, full viewing angles, and energy efficiency (low power consumption occurring only when changing the displayed information). Thanks to those, the excellent readability of the content presented on such displays is ensured. The only condition for an e-paper solution to function properly around the clock is to provide additional lighting at night.
Screens in validators
Another group of devices closely related to transport and actively using LCDs are ticket validators. These applications use various information display technologies, and the size of the screen itself usually influences their selection. In the case of devices requiring several-inch solutions, the economical 7-inch displays by Winstar are worth recommending. We propose 16- or 20-character and 2- or 4-line LCM displays with the 12 o`clock viewing for small, more common ticket validator formats, such as those seen inside vehicles. Winstar also produces models with such specifications.
The vision of the world without ubiquitous displays may seem soothing and in general harmony with nature. However, it is worth looking at the reality around us with a rational eye. Without displays deployed at the critical points in the transport infrastructure, and thus without the right media for transmitting important information, life would become very difficult for passengers. Even the slightest change in train and bus timetables would not be communicated effectively without the solutions that can be seen in public transport systems today. Contact us if you need any support in implementing your project.
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