The irony is, that despite the best of safety systems, the fault ultimately
comes down to human error.
The error may be in a driver assuming a signal will clear, the driver failing to
pay due care in the journey of his train due to drugs,sleep deprivation/fatigue,
and so on, or a mechanical failure through improper maintenance
programs/unskilled maintenance staff or faulty (paper) systems (ie people not
following a clear and defined process)
Even u-beaut hi tech (mechanical/electronic) systems can be overridden (agin
human error), just ask a disreputable car dealer to remove the speed limiting
function from your cars' ECM.
Safety and safety systems relies on trained, experienced people working with
systems that are practicable and over which they bear some control or at least
have some input into.
Nic