Thameslink ‘Core’ major disruption (04/04)

[Bald Rick]

Regular forum members are doubtless saying "I wonder when that Taunton bloke will be along again, to say surely such a key critical point should have a standby diesel loco in a siding at Blackfriars or Kentish Town, able to drag any breakdown out of the core in short order, like he needs to say about twice a year on average when it all goes wrong down there again".

So I will.

Incidentally, TfL nowe do exactly this at the nearby Blackwall road tunnel, breakdown truck sat there, instead of needing to be called, initially through peak hours, now all day I think.

wouldn’t have made any difference in this case. The train was moved (by itself) as soon as it was checked and safe to do so.

 

[akm]

As far as blaming the Driver. Nobody really know what happened unless they were the Driver themself or they are involved in the investigation. What will happen is that any learnings from the investigation will be passed down and acted upon.

Is this incident something RAIB would get involved with, or doesn't it count as an 'accident' ?

 

[AM9]

Is this incident something RAIB would get involved with, or doesn't it count as an 'accident' ?

From what we know, was anybody's safety at issue?

 

[Watershed]

The cost ratio will be insanely high. If you counted the number of trains doing a changeover, taking units out the Sidings, and generally making these moves on a daily basis. The number of incidents is a teeny tiny fraction. How much are you prepared to pay for it ?

It's happened twice in the last year. Obviously how much it costs is going to be a highly relevant consideration, but it's hardly great to admit "we're going to skip this expense and accept that the Core will avoidably go tits-up twice a year"!

You could say the same about SPADs or overspeeds really. "Well they don't happen very often, and it would cost a lot to stop them, so we'll accept them as the cost of doing business". The installation of TPWS etc. (at considerable cost) proves that this is not an acceptable way of dealing with things.

That is quite apart from the fact that there seems to be a fundamental oversight in the software here, as the 700s aren't designed to changeover on the move. So it should never be possible for the pan to be extended whilst the unit is taking power from the shoes.

 

[swt_passenger]

It's happened twice in the last year. Obviously how much it costs is going to be a highly relevant consideration, but it's hardly great to admit "we're going to skip this expense and accept that the Core will avoidably go tits-up twice a year"!

You could say the same about SPADs or overspeeds really. "Well they don't happen very often, and it would cost a lot to stop them, so we'll accept them as the cost of doing business". The installation of TPWS etc. (at considerable cost) proves that this is not an acceptable way of dealing with things.

That is quite apart from the fact that there seems to be a fundamental oversight in the software here, as the 700s aren't designed to changeover on the move. So it should never be possible for the pan to be extended whilst the unit is taking power from the shoes.

Changing on the move was definitely part of the DfT train technical spec, if you were to search through much earlier threads from before the trains ever arrived it was all well covered in these forums.

 

[43066]

You could say the same about SPADs or overspeeds really. "Well they don't happen very often, and it would cost a lot to stop them, so we'll accept them as the cost of doing business". The installation of TPWS etc. (at considerable cost) proves that this is not an acceptable way of dealing with things.

Actually I’d say that example rather proves the opposite - TPWS was adopted precisely because it was a good deal less expensive than mass roll out of the (more effective) ATP. Cost can never be totally excluded from these decisions and we are at the point where the railway is so incredibly safe that the law of diminishing returns means it’s difficult to justify more being spent on making it safer, or in this case less error prone.

That is quite apart from the fact that there seems to be a fundamental oversight in the software here, as the 700s aren't designed to changeover on the move. So it should never be possible for the pan to be extended whilst the unit is taking power from the shoes.

700s have to extend the pan when taking power from the shoes every time they go through City Thameslink, so it would presumably be difficult (for which read too expensive) to design a system that would allow this but simultaneously eliminate human errors like the one discussed above.

 

[Watershed]

Actually I’d say that example rather proves the opposite - TPWS was adopted precisely because it was a good deal less expensive than mass roll out of the (more effective) ATP. Cost can never be totally excluded from these decisions and we are at the point where the railway is so incredibly safe that the law of diminishing returns means it’s difficult to justify more being spent on making it safer, or in this case less error prone.

True - but TPWS was more expensive than the 'do nothing' option, which is being advocated by some in this case.

700s have to extend the pan when taking power from the shoes every time they go through City Thameslink, so it would presumably be difficult (for which read too expensive) to design a system that would allow this but simultaneously eliminate human errors like the one discussed above.

But not on the move. It's perfectly feasible to design a TMS that prevents the pan from being raised (or drops it if it's already up) if the wheels are moving under DC power. Which has been the root cause of each of these incidents.

Of course, that would still leave some potential edge cases, but it would completely eliminate the possibility of this particular kind of incident. Which, despite a briefing no doubt going out after the last incident, has happened again.

 

[43066]

But not on the move. It's perfectly feasible to design a TMS that prevents the pan from being raised (or drops it if it's already up) if the wheels are moving under DC power. Which has been the root cause of each of these incidents.

I suppose if, as per @swt_passenger ’s comment above, the trains were specified to be capable of changeover on the move (perhaps as future proofing) that might answer that point, and be very complex and costly to re-engineer.

EDIT: perhaps looking more closely at the ADD would be a better solution - it’s intended to prevent precisely this kind of incident by triggering a brake application if the pan extends with nothing above it. Of course it’s difficult do anything other than speculate without understanding the system in detail.

Of course, that would still leave some potential edge cases, but it would completely eliminate the possibility of this particular kind of incident. Which, despite a briefing no doubt going out after the last incident, has happened again.

It does seem like a strange one. Why does the set up at that location (on DC) involve raising the pan when it doesn’t when setting up at any of the DC locations south of the river. Possibly because there’s no GPS in Smithfield sidings? Perhaps a current TL driver could comment.

True - but TPWS was more expensive than the 'do nothing' option, which is being advocated by some in this case.

This time it might be “send a briefing out and also stick a sign up”.

 

[Bald Rick]

Is this incident something RAIB would get involved with, or doesn't it count as an 'accident' ?

no, RAIB would not be involved

 

[Fincra5]

313s used to have the Buzzer when you were on Both AC/DC, that you could override with a button, briefly. That could be a solution between City and Farringdon.

Another is Deadwire from City to Blackfriars, including the Apothecary Crossover. The TMS would quickly make you aware you had no juice.

Whilst it's not that common, there's definitely a reccuring theme for trains coming out of Smithfield.

 

[Bald Rick]

Another is Deadwire from City to Blackfriars, including the Apothecary Crossover. The TMS would quickly make you aware you had no juice.

that would just delay the issue, and mean the pan hits the first signalling gantry outside Blackfriars instead.

 

[Need2]

I suppose if, as per @swt_passenger ’s comment above, the trains were specified to be capable of changeover on the move (perhaps as future proofing) that might answer that point, and be very complex and costly to re-engineer.

EDIT: perhaps looking more closely at the ADD would be a better solution - it’s intended to prevent precisely this kind of incident by triggering a brake application if the pan extends with nothing above it. Of course it’s difficult do anything other than speculate without understanding the system in detail.




It does seem like a strange one. Why does the set up at that location (on DC) involve raising the pan when it doesn’t when setting up at any of the DC locations south of the river. Possibly because there’s no GPS in Smithfield sidings? Perhaps a current TL driver could comment.



This time it might be “send a briefing out and also stick a sign up”.

When you go into Smithfield’s you have to be in DC, this is why the signaller will contact you before clearing signals for you to proceed to ensure you are in DC mode only.
On the way out of Smithfield’s and going into City you have to be in DC as it is DC only.
The problems arise (as I think in the most recent 2 incidents) is when the unit stops at City platform for whatever reason (but still wants to travel south), the unit then automatically tries to go into AC mode and puts the pans up.
The brief after the last incident puts the onus fully on the driver to contact the signaller (going into Smithfield’s the onus is on the signaller) to tell them your pans are down and you are in DC mode.
I can only see it being the driver’s fault but as others have asked, should it be that easy to get wrong when you’d have thought it be quite easy to stop!

 

[Fincra5]

that would just delay the issue, and mean the pan hits the first signalling gantry outside Blackfriars instead.

What signalling gantry? The only Gantries are South Side...

When you go into Smithfield’s you have to be in DC, this is why the signaller will contact you before clearing signals for you to proceed to ensure you are in DC mode only.
On the way out of Smithfield’s and going into City you have to be in DC as it is DC only.
The problems arise (as I think in the most recent 2 incidents) is when the unit stops at City platform for whatever reason (but still wants to travel south), the unit then automatically tries to go into AC mode and puts the pans up.
The brief after the last incident puts the onus fully on the driver to contact the signaller (going into Smithfield’s the onus is on the signaller) to tell them your pans are down and you are in DC mode.
I can only see it being the driver’s fault but as others have asked, should it be that easy to get wrong when you’d have thought it be quite easy to stop!

Not entirely sure about that....

The system is setup for Bidirectional Working... so it shouldn't tell the train to do an Auto Changeover in that direction.

 

[Bald Rick]

What signalling gantry? The only Gantries are South Side...

I presumed you meant the ‘dead wire‘ would go through Blackfriars - otherwise the pan would rise in the station and dent the roof (like a few 319s did back in 2012-14)

 

[Need2]

The system is setup for Bidirectional Working... so it shouldn't tell the train to do an Auto Changeover in that direction.

Are you a driver?
When you drive south to north you must stop at City. As soon as you stop the ac/dc changeover automatically takes place, exactly the same at Farringdon when going north to south,
If you leave Smithfield’s to travel south the briefing states that if you stop at city platform you MUST contact the signaller to tell them that your pans are down and that you’re in dc mode. I can
Only assume this is because the changeover will take place when you don’t want it to. Unless it is to stop the driver wrongly performing a manual changeover.
Something or someone is putting the pans up.

 

[Fincra5]

I presumed you meant the ‘dead wire‘ would go through Blackfriars - otherwise the pan would rise in the station and dent the roof (like a few 319s did back in 2012-14)

Ah no. It wouldn't take you far beyond City, up hill, for the unit to realise you're off the AC Juice. You would notice something is up, hopefully...

Are you a driver?
When you drive south to north you must stop at City. As soon as you stop the ac/dc changeover automatically takes place, exactly the same at Farringdon when going north to south,
If you leave Smithfield’s to travel south the briefing states that if you stop at city platform you MUST contact the signaller to tell them that your pans are down and that you’re in dc mode. I can
Only assume this is because the changeover will take place when you don’t want it to. Unless it is to stop the driver wrongly performing a manual changeover.
Something or someone is putting the pans up.

Of sorts... like I say it shouldn't occur heading south... unless the Baliese has an issue.

 

[Bald Rick]

Ah no. It wouldn't take you far beyond City, up hill, for the unit to realise you're off the AC Juice. You would notice something is up, hopefully...

when all these incidents happen the unit is on dc., and knows it is off the AC.

 

[Fincra5]

when all these incidents happen the unit is on dc., and knows it is off the AC.

Indeed but the incidents, mostly, also happen between City and Blackfriars ...where there's no deadwire... especially if crossing over apothecary Crossover.

Dead wire would give am extra chance to spot the error by blackfrairs, especially are you're heading steeply uphill, first of all with halfpower, then none.

 

[Bald Rick]

Indeed but the incidents, mostly, also happen between City and Blackfriars ...where there's no deadwire... especially if crossing over apothecary Crossover.

Dead wire would give am extra chance to spot the error by blackfrairs, especially are you're heading steeply uphill, first of all with halfpower, then none.

the error is only spotted by the pan going up,hitting something, and causing the MCb to operate. A Longer stretch of wire doesn’t help that.
The answer to this must Lie on the train somehow.

 

[Western Sunset]

As far as I can make out, northbound the 3rd rail ends (on both tracks) at the north end of Farringdon's platforms. Southbound, the OHLE ends at the southern portal of the tunnel section south of City T'link station (and excludes S'field Sdgs, which are 3rd rail only. So the dual ac/dc extends from the north end of Farringdon to just south of City t'link. Is that correct?

 

[Fincra5]

the error is only spotted by the pan going up,hitting something, and causing the MCb to operate. A Longer stretch of wire doesn’t help that.
The answer to this must Lie on the train somehow.

I'm not talking about the ADD operation of a Pan...
You would notice the power dropping out on the HMI. There is a motoring Icon which would change from White to Yellow, Then Black. So you be aware you'd lost power before you even got to Blackfriars...

The lack of acceleration up hill would also be a clue.

It's about some more preventative measures..

As far as I can make out, northbound the 3rd rail ends (on both tracks) at the north end of Farringdon's platforms. Southbound, the OHLE ends at the southern portal of the tunnel section south of City T'link station (and excludes S'field Sdgs, which are 3rd rail only. So the dual ac/dc extends from the north end of Farringdon to just south of City t'link. Is that correct?

Correct.

 

[swt_passenger]

As far as I can make out, northbound the 3rd rail ends (on both tracks) at the north end of Farringdon's platforms. Southbound, the OHLE ends at the southern portal of the tunnel section south of City T'link station (and excludes S'field Sdgs, which are 3rd rail only. So the dual ac/dc extends from the north end of Farringdon to just south of City t'link. Is that correct?

Yes. Fitted since about 2009. But then it wasn’t in full use until 2013, the OH was earthed and raised until then due to it being fouled by Networkers and 375s that were still using Smithfield Sidings.

 

[387star]

What percentage of trains run ATO through the core now ? Believe they have a countdown timer so the driver knows when to close the doors! Presumably this wasn't an ATO move

 

[Western Sunset]

Just wondered; do both tracks have OHLE to the tunnel portal south of CT and is the scissors crossover (both legs) between CT and B'friars (in the tunnel) wired too? Presumably, the crossover south of Farringdon (just inside the northern portal of the tunnel) is wired too.

 

[Fincra5]

Just wondered; do both tracks have OHLE to the tunnel portal south of CT and is the scissors crossover (both legs) between CT and B'friars (in the tunnel) wired too? Presumably, the crossover south of Farringdon (just inside the northern portal of the tunnel) is wired too.

The Crossover south of CT is not wired... but the normal running lines have a solid bar above them.. like dead wire...

The issue with this train, 5V55, is it went over the Crossover (apothecary crossover) with the pan raised and there isn't any wire.

 

[Western Sunset]

Thanks. So the raised pan came to grief as the unit went over the scissors crossover to access the southbound line? So the train would've paused in the northbound plat at CT when the pan was raised.

 

[Horizon22]

Thanks. So the raised pan came to grief as the unit went over the scissors crossover to access the southbound line? So the train would've paused in the northbound plat at CT when the pan was raised.

Yes, the only way to get from Smithfield southbound is via the Northbound line and cross over south of City Thameslink. Then would have stopped in the small open section before arriving at Blackfriars (as the original photo suggests).

For whatever reason, the procedures weren't followed correctly with this particular move and the pan was raised whilst still leaving.

 

[Need2]

So what is actually causing this,
Simple driver error or a fault with the train itself?
I can only see it as driver error, they either initiated a changeover when they shouldn’t or they didn’t take any notice when (if) the train did the changeover automatically.

 

[Horizon22]

So what is actually causing this,
Simple driver error or a fault with the train itself?

I would lean towards driver error. The pan should have a) never been raised leaving Smithfield or b) raised automatically at CT and then lowered manually and the signaller advised (as others have upthread have suggested is the process). Evidently for some reason, this didn't happen.

 

[Western Sunset]

Thanks.
So 1. driver error or 2. pan automatically raised when train was standing in northbound plat at CT waiting to go south.