Passenger Information System (PIS)
A passenger information system delivers announcements, next-stop displays, service updates and advertising to passengers on trains and in stations. Onboard, it typically shares the train's Ethernet network with control and diagnostic systems and connects to the ground through cellular links to receive live content.
How it works
Onboard, a PIS server receives the train's location and door status from the Train Control and Management System, matches it against a route database and drives displays and speakers throughout the train. It exchanges data with the operator's back office over a cellular or Wi-Fi link for real-time service information, connection times, content updates and remote diagnostics.
In stations, display and public-address systems are fed from the traffic management system and a central content platform, often running on standard IT servers and networks. Many systems also integrate with CCTV, passenger counting and emergency communication functions.
Why it matters for security
PIS is not a safety system, but it is one of the most connected systems on a train and in a station, with an always-on link to the outside and a position on the same physical network as vital equipment. It is the system most likely to run commodity software with known vulnerabilities and the most common entry point in reported rail incidents, from defaced displays to ransomware in station systems.
The security question is less about the displays themselves than about what a compromised PIS can reach. Segmenting it from control networks and monitoring for unexpected communication between passenger-facing and operational systems are among the first steps in securing rolling stock.
Related solution
Securing rolling stock across mixed fleets and vendors
Detecting when passenger-facing systems start talking to control systems they should never reach.
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