towerman
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Post by towerman on Aug 2, 2022 9:34:59 GMT
When 67TS was operating The Victoria Line every train had to be code tested every 24 hrs like conventional stock had to have the tripcock tested.Is something similar done on ATO stock these days? .
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class411
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Post by class411 on Aug 2, 2022 13:20:15 GMT
Not that I can answer you question, but what is 'code testing'?
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towerman
My status is now now widower
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Post by towerman on Aug 2, 2022 17:20:48 GMT
The old Victoria Line system ran on codes,420-full speed running,270- controlled speed running,180-approaching red signal,120- not recognised by the train used to prove track circuits.In the depot and Walthamstow,Victoria & Brixton Sdgs there were code boxes at each end of the stabling road,you opened up the train switched on the box and checked that the code trip valve held in on 420,270 & 180 codes and dropped out on 120.Doing a code test on an outstabled train you had to remember to switch off the box when you finished or the outlet signal wouldn’t clear!!!
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Post by spsmiler on Aug 2, 2022 17:26:07 GMT
Not that I can answer you question, but what is 'code testing'? With respect of the 1967ts, possibly it was checking the accuracy of the mechanical equipment on the train to detect / count the coded impulses that the signalling system fed in to one of the running rails and which told the automated train control system when to accelerate brake, coast etc. In those days everything was mechanical - quite literally 'clockwork' technology! btw, the image below is a close-up view of the front left of a 1967ts train showing the receiver unit which detected the codes used by automatic train operation system. It was filmed at a depot open day - possibly Acton depot in 1983. Also seen is a little-used rusty live power rail.
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Post by t697 on Aug 2, 2022 20:17:58 GMT
When 67TS was operating The Victoria Line every train had to be code tested every 24 hrs like conventional stock had to have the tripcock tested.Is something similar done on ATO stock these days? . It is a requirement that ATC trains do have to do an equivalent test at least daily. The different ATC systems accomplish this in different ways.
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class411
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Post by class411 on Aug 3, 2022 10:13:21 GMT
I'm beginning to find this thread seriously worrying.
If these checks are necessary because the equipment being tested is safety critical, what is protecting trains during the up to 24 hours they may be running with faulty equipment between tests?
Also, for any type of ATO, all systems should be fail safe. If any part does fail safe, surely that would immediately register a fault, so potentially 'after the event' testing should be superfluous.
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Post by t697 on Aug 3, 2022 12:25:59 GMT
Also, for any type of ATO, all systems should be fail safe. If any part does fail safe, surely that would immediately register a fault, so potentially 'after the event' testing should be superfluous. Yes these systems are high integrity 'fail-safe'. In part that relies on 'no single point wrong side failure' causing a hazardous condition. In principle the routine testing described assures that no single point failure has happened either, stepping down the remaining integrity. The systems have in service automated checking too. Probably not appropriate to go into every detail here. Mod edit [Antharro]: Quote partially removed. Please be selective about the part of a post you wish to quote rather than the whole post verbatim, particularly if you are replying to the previous post in the thread.
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Post by zbang on Aug 3, 2022 17:09:57 GMT
Also, this sort of testing happens under controlled conditions and (I assume) checks all the codes, not just any usual ones. It's kind of like a brake test when leaving the depot*- they ought to work, but let's check anyway.
*I assume this is performed, it's normal on some transit systems.
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