Waterloo station - collision and derailment, 15 Aug 2017

[whole diary]

[Gordon the Blue Engine]

I wonder whether perhaps the points were set wrong when the inward working entered P13 some 20 minutes earlier.  This “trailing” of the points would not of course have caused a derailment, but would have damaged them and could have lead to the 0540 outward working derailing when passing over them. 

Partial/complete replacement of the moving bits of the points may be necessary, which they may have decided to postpone for now.

[paul7575]

On the WNXX^▸ (Stored Unserviceable, Mainline Locos HQ All Classes) Forum it was mentioned that the derailed train (once rerailed) was stabled in Platform No.13 so perhaps its still there?

I believe it ran to Clapham Yard yesterday morning about 0815, 5Z50 was the train ID mentioned elsewhere. I think I saw it in P11 on the opentraintimes map beforehand but cannot be sure.

Paul

[paul7575]

I wonder whether perhaps the points were set wrong when the inward working entered P13 some 20 minutes earlier.  This “trailing” of the points would not of course have caused a derailment, but would have damaged them and could have lead to the 0540 outward working derailing when passing over them. 

Not sure about this 'inward working to P13'?  The incident train was leaving P11, there have been various images online showing the majority of the train still in P11 after the event.  Another unit was trapped in P12 after the incident, and P13 was inaccessible, but IIRC^▸ (if I recall/remember/read correctly) empty at the time.

This Guardian article shows the aftermath, the barrier train being in the P10 approach:
https://www.theguardian.com/uk-news/2017/aug/16/rail-passengers-second-day-delays-waterloo-derailment

Paul 

[bradshaw]

from the SWT^▸ (South West Trains) journey check

Following a low-speed partial derailment on Tuesday, we are unable to use platform 13 at London Waterloo. Engineers attempted repairs overnight but were unable to complete them without causing significant disruption to morning services. As a result, the work to bring the platform back into use will take place overnight on Thursday 17 August.

[paul7575]

from the SWT^▸ (South West Trains) journey check

Following a low-speed partial derailment on Tuesday, we are unable to use platform 13 at London Waterloo. Engineers attempted repairs overnight but were unable to complete them without causing significant disruption to morning services. As a result, the work to bring the platform back into use will take place overnight on Thursday 17 August.

That's just as you'd expect, (as post #47) - hence P11 and P12 are in use, (trains in there as I write) which indicates that the affected crossing is presently out of action and must be locked in position for 'straight across' moves from P11 or P12 towards the Up Main Relief.

It doesn't mean the original incident concerned trains entering or leaving P13 at all.

Paul

[Gordon the Blue Engine]

I wonder whether perhaps the points were set wrong when the inward working entered P13 some 20 minutes earlier.  This “trailing” of the points would not of course have caused a derailment, but would have damaged them and could have lead to the 0540 outward working derailing when passing over them. 

Not sure about this 'inward working to P13'?  The incident train was leaving P11, there have been various images online showing the majority of the train still in P11 after the event.  Another unit was trapped in P12 after the incident, and P13 was inaccessible, but IIRC^▸ (if I recall/remember/read correctly) empty at the time.

This Guardian article shows the aftermath, the barrier train being in the P10 approach:
https://www.theguardian.com/uk-news/2017/aug/16/rail-passengers-second-day-delays-waterloo-derailment

Paul 

Sorry, my mistake, I should have said P11 not P13.

...[later]  and RTT^» (Real Time Trains - website) shows the train in P12 arrived after the train in P11, so that's my theory blown out of the water!

[paul7575]

Sorry, my mistake, I should have said P11 not P13.

...[later]  and RTT^» (Real Time Trains - website) shows the train in P12 arrived after the train in P11, so that's my theory blown out of the water!

No problem.  We are back on the same song sheet again...   

Paul...

[stuving]

In that London Connections piece, it says:

In the end, however, the additional closure of platform 10 was required, due to the need for a barrier train at the end of platform 10 and across the Up Main Fast.

I'd been thinking that was at least a likely reason, and also speculating why - probably that plan A for blocking that path (clipping) was impractical for just those bits of a double slip crossing, and plan B (temporarily changing the interlocking) might also be too difficult. The comments after that article suggest the same things, and add that testing any modified interlocking was a big job in itself.

If you look at the way the possession has changed each weekend, not just for the bank holiday, that means that whatever was done to that crossing needed to be undone and redone several times. That would have added to the difficulty of either plan.

During each weekend, the possession covers all four main lines out to Queenstown Road, leaving the passenger service only three tracks - fingers crossed nothing breaks there! It also means all possessed platforms are reached via a sizeable parking area for engineering trains. During the week, only the slow lines are taken over, meaning that platforms above 7 can only be reached via the West Crossings. But that's how trains in service get between the Main Fast Lines and their platforms. I'm guessing that was seen as the main danger point, though not one that can really be avoided.

[GBM]

From RAIB^▸ (Rail Accident Investigation Branch) today (30th) 10h01
https://www.gov.uk/government/news/collision-near-london-waterloo-station-15-august-2017



News story
Collision near London Waterloo station, 15 August 2017
From:Rail Accident Investigation Branch Published:30 August 2017
Investigation into a collision near London Waterloo station, 15 August 2017.

Passenger train and wagons after the collision at Waterloo
Passenger train and wagons after the collision at Waterloo
At around 05:42 hrs on Tuesday 15 August 2017, a passenger train leaving London Waterloo station travelling at about 11 mph (18 km/h) collided with a stationary train of wagons. There were no injuries, but both trains were damaged and there was serious disruption to train services using the station.

The passenger train was the 05:40 hrs South West Trains service from Waterloo to Guildford and comprised 10 coaches, a combination of class 455 and class 456 electric units. The wagons were standing on a line adjacent to the intended route of the passenger train and had been provided as a safety barrier separating passenger services from an area where construction work was being undertaken as part of the Waterloo station upgrade project.

The collision occurred because a set of points were misaligned and directed the passenger train away from its intended route. The misalignment was a consequence of a temporary modification to the points control system which also caused the train driver and signaller to receive indications that the points were correctly aligned.

Our investigation will examine:

the circumstances leading to installation of the temporary control system modification
the safety measures provided while the temporary modification was in place
the checking and testing procedures applicable to the modification
any relevant underlying management factors.

[grahame]

From RAIB^▸ (Rail Accident Investigation Branch) today (30th) 10h01

The collision occurred because a set of points were misaligned and directed the passenger train away from its intended route. The misalignment was a consequence of a temporary modification to the points control system which also caused the train driver and signaller to receive indications that the points were correctly aligned.

Interesting to see this initial report ... removing the possibility of it being a SPAD^▸ (Signal Passed At Danger) or a signaller's error

[Oxonhutch]

To those of us who have undertaken risk assessments, it is always about one's position in the matrix bounded by likelihood - on the one hand - and consequences on the other, and what mitigation you employ in each part of that risk space. To my eyes, the barrier train did exactly what it was supposed to do in these circumstance.  It looks to me like it was the blunt, but all powerful, back-stop against a risk that was very unlikely, but with huge negative consequences if it happened.

I will be interested to see the RIAB look into the risk assessment programme.

[Electric train]

To those of us who have undertaken risk assessments, it is always about one's position in the matrix bounded by likelihood - on the one hand - and consequences on the other, and what mitigation you employ in each part of that risk space. To my eyes, the barrier train did exactly what it was supposed to do in these circumstance.  It looks to me like it was the blunt, but all powerful, back-stop against a risk that was very unlikely, but with huge negative consequences if it happened.

I will be interested to see the RIAB look into the risk assessment programme.

Although the barrier train was more likely to prevent construction site RRV^▸ (Road Rail Vehicle) incursion onto the operational railway than operational rail vehicles incursion into the construction site.

Having been in many rolls which have involved signing off on work similar to this the report will be interesting to read to see if it was process or human failure or a combination of the two,

[Oxonhutch]

Although the barrier train was more likely to prevent construction site RRV^▸ (Road Rail Vehicle) incursion onto the operational railway than operational rail vehicles incursion into the construction site.

I agree you that an RRV excursion was always more likely, or a trolley for that matter.

[eightf48544]

From RAIB^▸ (Rail Accident Investigation Branch) today (30th) 10h01

The collision occurred because a set of points were misaligned and directed the passenger train away from its intended route. The misalignment was a consequence of a temporary modification to the points control system which also caused the train driver and signaller to receive indications that the points were correctly aligned.

I would also have  expected the point in question to be clipped and padlocked as well as relying on "A temporary modification to the points control system". Might burn the point motor out!

[paul7575]

I would also have  expected the point in question to be clipped and padlocked as well as relying on "A temporary modification to the points control system". Might burn the point motor out!

It is a double slip crossover, with four routes/positions.    IIRC^▸ (if I recall/remember/read correctly) from other discussions there are four separate points machines, and four possible positions of the crossover.   AIUI^▸ (as I understand it) they cannot be partially clipped out of use because of the way the moving blades have to interact.   Clipping it in one position, say UMR to P12/13, would have taken P11 out of use. (or vice versa.)

Paul