I wonder, how extensive is the adoption of TPWS in the UK? I was under the impression that there are still lines that only have AWS, although they may be ones with little traffic or freight only. (TPWS is an ATC type system that will stop a train if it passes a red signal, whereas the older AWS only provides a warning that the driver must acknowledge else the brakes are applied.)
I was denied access to the video due to my location allegedly
The interesting thing is that unless these human actor protocols and operating procedures are fixed no amount of PTC or Kavach will prevent these sorts of accidents since these automation systems would be perfectly happy with what are essentially inputs at variance with reality (absent independent means of verification of consistency), i.e. not reflecting reality. In automation systems, for them to work right, the real state of the system must be reflected accurately to the system so that actions that it takes based on that information, that is reified into reality are consistent with reality. If not then things like train getting a green signal on the main runs off into a loop and crashes into something will happen. Unfortunately human beings can be very resourceful in screwing up.The Frontline item draws the same broad conclusions as the video does.
It is very hard to make something idiot-proof because idiots are very ingenious. It is even harder to make something resistant to mistakes made by intelligent people who generally know what they are doing.
One very sad thing in the article is the last sentence: A month after the accident, more than 80 of the people killed had not yet been identified.I was denied access to the video due to my location allegedly
As for the lessons learned from the Bahanaga Bazar accident here is a good article (over and year old article now):
https://frontline.thehindu.com/news...rain-accident-at-balasore/article67039892.ece
There was a similar accident at lower speed involving an Amtrak train in Michigan for surprisingly similar causes sometime back. In that case an Amtrak train inadvertently went into a siding at speed and derailed even though it had a clear signal on the main line. It happened because of improper wiring in a connection hut that S&C staff were working on.
I understand the mechanical system, on the London Underground has since been replaced by a more modern electronic system. I'm not sure if all lines have switched over yet, or whether it is still work in progress. Anyway, this is stated as being one of the reasons that heritage trains cannot be operated as freely as they could in the past, including the highly popular annual "Steam on the Met" event.
The issue of de-skilling and absence of institutionalized memory is indeed a big problem. I have seen plenty of examples in my own career with things being thrown away or ripped out because nobody could work out what they were there for, only to result in something going haywire many years down the line because of a special situation this seemingly redundant code or sensor was installed to prevent. And this even though it was fully documented (but who bothers to check paper documentation).And if everything is working normally, none of these safety systems will ever kick in, and at some point some bean counter will ask "why are we doing this? Doesn't the system KNOW where all the trains are?", and the original designers having long since moved on, the current maintenance staff will not know why the system was built that way and will do something they think is harmless, like replace the GPS feed with a clone of the track sensor feed, which will work fine until a track sensor fails at a bad time. Meanwhile, the railroad will save lots of money by not maintaining the redundant systems
