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overspeed protection has been standard on most national railways for decades is there any reason they invented a new system (expensive and slow to rollout) vs.
by blibble 9y ago
overspeed protection has been standard on most national railways for decades
is there any reason they invented a new system (expensive and slow to rollout) vs. using an existing tried and tested one?
the main UK system (there are two) is nothing to write home about, but it is gloriously simple and was very fast and cheap to deploy: two metal transmitters live in the track bed coming up to a hazard, spaced such that they are 1 second apart at the maximum speed
if the train detector passes over both in less than 1 second then the brakes are triggered automatically
they look like this: https://en.wikipedia.org/wiki/Train_Protection_%26_Warning_System#/media/File:Tpws_loop.jpg https://en.wikipedia.org/wiki/Train_Protection_%26_Warning_S...
- cpitman 9y agoPTC is a lot more than overspeed control, imagine any use case that would be enabled by electronically controlled trains connected to a highly available network.
- blibble 9y agoperfect is the enemy of good TPWS was always a stopgap (rolled out in the 90s while ETCS was being developed); as I said it was cheap and easy to deploy, and has prevented many accidents exactly like this one for 25 years ETCS does what you are describing, and has been live in the UK and Europe since the early 00s it works, and is slowly being rolled out everywhere replacing TPWS so, again, why re-invent the wheel? even the Chinese are adopting it