Also, railways are not really meant to be safe against attackers with physical access to it (so basically anyone). For example, the sensors/switches on a railwa

Also, railways are not really meant to be safe against attackers with physical access to it (so basically anyone). For example, the sensors/switches on a railway that cause a train to perform an emergency halt if the train driver misses a stop signal can be modified by anyone near it - no encryption, no locks (source: https://www.youtube.com/watch?v=xwaKYZfgY8k https://www.youtube.com/watch?v=xwaKYZfgY8k - only in German though). You don't even need explosives, a simple wedge welded on a rail would be enough. In the end, I don't think it is economically feasible to secure a railway against that (as well as any other kind of track). You have to make sure that nobody does stupid things like these.