I would suggest the rail industry should look at IP based systems with care, particularly for control systems as they could be hacked. Although whether you could actually alter the software to set a confliciting route without the signalman noticing or an alarm being raised is an interesting question. You would need an intimate knowledge of the interlocking and signal control language to do such a thing.
Don't forget the last head on collsion was caused by a SPAD▸ coupled with the failure to provide flank protection. The software worked as programmed.
Currently using private wires it is difficult to hack but as we have seen they are vunerable to cable theft, although I suppose that will still be the case as each signal, point and track circuit is not going to have it's own broadband connection to off the railway, unless we go wireless.
With
ETCS▸ level 2 there are not fixed signals and no track circuits (other than in the
UK▸ we will use track circuits at junctions) axle counters are used these can have individual IP addresses and even at level 1 IP addressed equipment is possible.
Most of this comms will still be on internal systems with several layers of firewalls to the outside world