The tragic accident at Grayrigg has highlighted the on-going need for adequate surveillance of vulnerable points components without recourse to endless track walking.
I understand that a track inspection vehicle fitted with video equipment had passed the scene some two days prior to the accident, but, inevitably, the huge volume of data recorded was awaiting processing.
For the past 10 years London Underground has been developing and using its AVI video system. This, combined with a computer database, enables the recipient of the video recordings to access designated priority features almost instantly.
Video surveillance has always been an attractive prospect, but as anyone who has ever studied output tapes will know analysis is difficult, time-consuming and boring. LU recognised this, hence its successful prioritised access feature.
Paul Leech (M), PaulLeechNB9@aol. com