The 83 page report has relatively little to say about the train continuing its progress for four miles following derailment, until the signaller concluded that the growing list of track circuit failures (and a point detection failure) warranted stopping the train for examination.
The report refers to a couple of European standards bodies/committees and their analysis of wagon derailment monitoring equipment, which apparently concluded that
the cost of fitting and maintaining derailment detectors
could not be justified on safety grounds alone. There was a better case for
fitment based on economic grounds, in terms of less infrastructure damage to
repair after a derailment
Now these things are difficult to quantify. The conclusions may well be justified if spending that money elsewhere could prodice a
safer railway.
However, beware of "black swans" - things that happen in defiance of conventional risk analysis. Beware also of creeping changes in practice that cause risks to grow and have contributed to some of the major rail incidents of modern times.
This particular derailment was a consequence of dodgy track on a secondary route, but some other type of derailment causing four miles of damage with possible running foul of adjacent lines...platforms...on a busy route could be a lot worse in impact - and even without injuries, closing the line for several days.
I don't particularly wish to lead a demand for ever-more safery paraphernalia. But as the eyes and ears that may detect such derailments are removed from trains...signalboxes...stations...crossings...I don't wish us to sleep-walk into another version of Newton, Hatfield or Southall.
