Equipment failure:
For starters, I was more talking about signalling failures. What if there is a fault with the ERTMS equipment (albeit nothing will probably happen, but hey ho), or a fault develops on the train a million miles from anything close which stops it dead in it's tracks?
Increasingly in britain is hard to find sites truly remote.
What could happen is the train behind it (and in almost all cases there will be one) would close in behind the train under control of the central centre, couple using the standard autocouplers and shove the train to the next station. (ETCS can be calibrated for the control unit to not lead the train).
Or if a train needs evacuating?
A train with one or two crew members is not going to be significantly easier to evacuate than one without crew.
The passengers will detrain themselves and will be impossible to control, as we have seen elsewhere.
And police helicopters and ground units would arrive relatively quickly on the vast majority of the network.
If a train loses communication with the control center, how would you use cameras to react?
You would use cameras on
other trains that were nearby on our rather intensively operated network or were positioned around the network for other purposes.
(This is the era of big data, we can access any IP enabled camera anywhere on the system at the touch of a few keys).
If no units were available to look you would just send someone to look, be they railway personnel or the police - since it will be a fairly rare occasion.
Also, I'm not sure which intrusion alarms your thinking of using, but will they cover UWCs, platform ramps, level crossings, places were there is no fence/broken fence (these are probably more common than you realise), how would you detect them?
Putting an eight foot high concrete wall around railway property would cost peanuts if it was required.
Platform ramps are increasingly being obliterated for the reasons you describe, and level crossings are hardly the flavour of the month and are also slowly being eliminated.
The railway's isolation is rapidly increasing. It might not yet be hermetic but it is approaching that surprisingly rapidly.
Trains wouldn't work using sensors as how would it distinguish between track staff and trespassers?
The control centre will presumably be told where the track staff are.
The train would report that it had detected people sized moving objects on the track - not that they were trespassers.
Since control knows where the people authorised to be on the track are it knows that people found at position x can't possibly be authorised.
And train faults, your talking about computers here. They fail. What about access doors left open leaving depots (ok, you could fit a door open sensor on everyone.., or gauge detectors in the depots),
Why would we not have gauge detectors?
Its relatively cheap and it avoids expensive problems when things get ripped off.
And door/hatch open sensors are very cheap to fit.
So you are going to replace all the old trains as well!
Are you proposing to keep all old trains in service forever?