It really depends if these systems (that appear to control arrival boards) are on a network or not. If they’re not, then there is minimal risk to leave them the way they are. Somebody would need physical access to the devices to do harm. If they are on a network then that’s a pretty big deal, but some attacks could be mitigated against by tunnelling and/or additional packet filtering to ensure the integrity of messages.
Continuing on a railway theme you should be FAR more worried all the devices that run up and down the side of railway lines - PLCs that talk with each other and operations centres to control things like lights, junctions, crossings etc. If they’re more than 5 years old then chances are then all that traffic is in the clear, and because these things live in boxes by the railway line, it wouldn’t take much to break into a network and potentially kill people by running two trains into each other.
Well yes. You can code software remotely. That doesn’t mean the end system is reachable through the network. Given it’s DB, I bet these systems are still patched by floppy. Until very recently they’ve used floppy’s to distribute train schedules to be displayed in the train.
