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| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 19/12/2019 at 18:44 #122347 | |
Edgemaster
332 posts |
Today, RAIB have released their final report into the loss of Temporary Speed Restriction data from the Cambrian line's ETRMS system following a reset. It's an interesting read for those with an interest in modern signalling systems design (and how not to do it), some serious system design missteps by the system provider Ansaldo (now Hitachi) that were also missed during the safety certification process by a consultant, and at sign-off by Network Rail (likely due to lack of experience with ETRMS at the time within the company). https://www.gov.uk/government/news/report-172019-loss-of-safety-critical-signalling-data-on-the-cambrian-coast-line Log in to reply |
| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 19/12/2019 at 20:28 #122348 | |
jc92
3685 posts 
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Is it worth also adding this to the RAIB reports thread for future reference?
"We don't stop camborne wednesdays" Log in to reply |
| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 19/12/2019 at 22:42 #122350 | |
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Edgemaster
332 posts |
jc92 in post 122348 said:Is it worth also adding this to the RAIB reports thread for future reference?The RAIB reports thread is already missing a lot. I'd assumed that this specifically signalling-related incident deserved its own thread on this board, as was likely to generate discussion, rather than letting it get mixed in with others. Last edited: 19/12/2019 at 22:43 by Edgemaster Reason: None given Log in to reply |
| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 20/12/2019 at 08:21 #122356 | |
sorabain
72 posts |
"The temporary speed restriction had been applied at this location since 2014 to provide level crossing users with sufficient warning of approaching trains so they could cross safely." Why isn't this a "permanent" speed restriction? Log in to reply |
| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 20/12/2019 at 11:15 #122360 | |
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Muzer
718 posts |
sorabain in post 122356 said:"The temporary speed restriction had been applied at this location since 2014 to provide level crossing users with sufficient warning of approaching trains so they could cross safely."This was mentioned later on in the report - Network Rail had planned to close or upgrade all the crossings in question. But they hadn't done so by the point of the crash, and so the TSR had stood for much longer than NR guidelines. But NR didn't believe this to be a problem because of the reduced driver workload needed to remember long-standing TSRs on the Cambrian due to them being integrated into the in-cab signalling. But RAIB disagreed. Log in to reply |
| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 20/12/2019 at 13:32 #122362 | |
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Edgemaster
332 posts |
Muzer in post 122360 said:But RAIB disagreed.RAIB didn't disagree, they noted that it should have been of no consequence, had the ERTMS system met its specified SIL 4 rating. Their recommendation was that the system should be fixed, and not that the TSRs should be made permanent, nor any recommendation that drivers should change behaviour: Quote: The Cambrian ERTMS does not rely on drivers’ recollection of this information, as the combination of the permitted speed displayed on the DMI and automatic supervision of the speed of the train by the ERTMS equipment provides the necessary assurance. However, drivers are still required to familiarise themselves with temporary speed restrictions on the Cambrian lines and report if they are not shown on the DMI. Log in to reply |
| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 20/12/2019 at 20:03 #122369 | |
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Muzer
718 posts |
I feel like that's still saying that they'd rather not, if you read between the lines: "The long-term retention of temporary speed restrictions [...] are undesirable in ERTMS equipped areas and not in accordance with the intent of the rail industry standards." seems pretty clear to me that RAIB don't approve...
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| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 20/12/2019 at 20:23 #122371 | |
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Edgemaster
332 posts |
I had read that statement with the interpretation that existing standards didn't take into account the additional safeguards that ERTMS operation should give for TSRs (above and beyond the usual protections that are associated with TSRs).
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| RAIB report 17/2019 published: Loss of safety critical signalling data on the Cambrian Coast line 21/12/2019 at 09:14 #122375 | |
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kbarber
1742 posts |
I would follow Muzer's interpretation. If you ever watched Yes, Prime Minister you'll know that in Civil Service-ese 'undesirable' is an industrial-strength hint.
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