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Cambrian Line Radio Signalling failure - RAIB investigating


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54 minutes ago, corneliuslundie said:

And I agree that the protection should be such as to protect the whole installation rather than some way down the equipment chain.

BTW what has all this got to do with the Cambrian line other than the fact that its signalling is electronic and therefore susceptible to such things?

Jonathan

 

Nothing as such - but as Caradoc noted...

 

On 21/12/2019 at 10:22, caradoc said:

I do agree however that the technology and systems must be made 100% reliable, with back-ups; I was involved in far too many loss of signalling incidents as a Controller ! And just in the last few days major disruption was caused in the London Victoria and Glasgow Central areas due to signalling failures.

 

An 'over voltage event' has the potential to be just as disastrous to the Cambrian system, or the ECML should the plans to do away with lineside signals come to pass as planned...

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Any kind of event which trips the signalling power supply off will be likely to stop the job in the affected area.

 

Over voltage is pretty rare from the grid, especially at peak times (when load is greatest so most voltage drop over the conductors), so it's not something to get too worked up over. It'll happen very occasionally, but the only way to tolerate it without the protection operating is to increase the capability of the equipment to withstand over voltages. And that means the whole system.

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7 hours ago, phil-b259 said:

It is of course possible to construct advanced power supply systems that would be able maintain supplies in the event of an over voltage input  - but these are not 'off the shelf' items as it were.

 

I think that New York has installed external voltage regulators before the UPS systems to protect against over-voltages, which were  becoming more common.

 

When we installed signalling systems in Thailand, India, Pakistan etc we would always ensure that the power supplies were capable of dealing with the relatively unstable incoming power. I guess UK is heading that way.

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12 hours ago, Zomboid said:

Any kind of event which trips the signalling power supply off will be likely to stop the job in the affected area.

 

Over voltage is pretty rare from the grid, especially at peak times (when load is greatest so most voltage drop over the conductors), so it's not something to get too worked up over. It'll happen very occasionally, but the only way to tolerate it without the protection operating is to increase the capability of the equipment to withstand over voltages. And that means the whole system.

In the UK, over voltages may not be common, but instances of momentary under voltages tripping out computer based signalling equipment are happening on a virtually daily basis, with consequent bicycle clip moments for train drivers having signals revert to red in front of them without warning. Compared to relay interlockings, it's one area where the arrival of electronics has not been a step forward.

 

Jim

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  • 5 months later...
On ‎20‎/‎12‎/‎2019 at 22:22, big jim said:

There is ERTMS but also a couple of real ground signals to allow you in and out of the depot/yard that are controlled by the same signalling centre, doing that allows movements around the shed without having to be in the system at level 1 

 

 

wouldn't you be in level 0 in the yard?

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42 minutes ago, St. Simon said:


No, you would be on Level ‘NTC’ , Level 0 is for possessions rather than yards and depots.

 

Simon

Not necessarily.

 

If the yard/depot is defined as a shunting area, a fitted vehicle would be permitted to operate in any ETCS level in ETCS modes 'SH', 'PS' or indeed even 'NL' in certain cases.

 

UNISIG subset 026-4.

 

In fact, there are lots of possibilities for 'modes' as opposed to 'levels'.

Edited by leopardml2341
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2 years since I have done ERTMS and it’s still a mind boggler, I can’t even remember what PS mode is! 

 

before I go anywhere near the Cambrian again I’m going to have to do a full refresh, I have had an interview at GB regarding refreshing and training on ERTMS again but away from the Cambrian with an updated in cab system on one of our locos but I’ve not heard anything back about it (this thread has reminded me to Chase it up!)  

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59 minutes ago, leopardml2341 said:

Not necessarily.

 

If the yard/depot is defined as a shunting area, a fitted vehicle would be permitted to operate in any ETCS level in ETCS modes 'SH', 'PS' or indeed even 'NL' in certain cases.

 

UNISIG subset 026-4.

 

In fact, there are lots of possibilities for 'modes' as opposed to 'levels'.


Hi,

 

I know that this is true within generally in ETCS, I know that the application in the UK (at the moment) is Level 0 is for possessions and Level NTC is being used in yards and depots.

 

Simon

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