Derailment at Kirkby (Merseyside) - 13/03/2021

[Grumpy Git]

The block is only for the walkway. Why anyone would think it has anything to do with stopping the train can only be down to its actual location.

 

[the sniper]

The footage from the CCTV camera mounted inside the arch should make for some interesting viewing.

Indeed! That's when it'll get on the news!

 

[Mcr Warrior]

Somewhat unusual if a bridge bash caused by a train is affecting local road traffic in the area (presuming it's the B5192 up above?)

Normally it's the other way round!

 

[Taunton]

Although the block itself is the pedestrian walking route, so not sure putting that in the firing line is "for the best", other than what was a cheap and cheerful solution in the 1970s.

No different to the many termini with the concourse immediately behind the stops.

 

[Bletchleyite]

ITV Granada region pòsted the story at 11.46.

BBC North West haven't posted any news at all. Presumably they don't work Sunday mornings.

It's probably also low down the list of news because a good many people aren't using it at the moment anyway, because leisure travel is discouraged.

 

[Ianno87]

No different to the many termini with the concourse immediately behind the stops.

Although that's not modern practice any more, e.g. Kings Cross has frangible platforms immediately behind the stops, Paddington has some overrun behind the buffers into "empty" concourse etc.

 

[Wezz]

The footage from the CCTV camera mounted on the underside of the overbridge arch should make for some interesting viewing.

If it gets released by someone, which I kinda hope it does once the investigation concludes.

 

[John Luxton]

Does anyone know if Kirkby and Ormskirk are the only locations where this split platform arrangement exists on the UK network?

Is it inherently dangerous given that this is the second time it has occurred at Kirkby?

Switching the clock back to the 1970s when the arrangement was implemented first at Ormskirk and then later at Kirkby might not a safer arrangement have been devised?

Perhaps with and island platform with one line on each side for cross platform interchange as it is more passenger friendly especially in bad weather(Yes I know at Kirkby the cutting would mean some serious earth works)?

If there was an island platform enough space could be left for accidental over-runs.

One wonders if outcome of the investigation might be a criticism of this split platform arrangement?

 

[Ianno87]

If it gets released by someone, which I kinda hope it does once the investigation concludes.

Depends which way it was pointing at the time.

Does anyone know if Kirkby and Ormskirk are the only locations where this split platform arrangement exists on the UK network?

Is it inherently dangerous given that this is the second time it has occurred at Kirkby?

Switching the clock back to the 1970s when the arrangement was implemented first at Ormskirk and then later at Kirkby might not a safer arrangement have been devised?

Perhaps with and island platform with one line on each side for cross platform interchange as it is more passenger friendly especially in bad weather(Yes I know at Kirkby the cutting would mean some serious earth works)?

If there was an island platform enough space could be left for accidental over-runs.

One wonders if outcome of the investigation might be a criticism of this split platform arrangement?

Modern standards would not simply permit such a design to be newly installed today. At Kirkby, a solution is on the horizon in the form of Headbolt Lane. Should the investigation discuss this, it will recognise the standards have moved on.

The priority in the 1970s was doing it cheaply, when the safety consequences were not given the same level if consideration.

 

[Bletchleyite]

Does anyone know if Kirkby and Ormskirk are the only locations where this split platform arrangement exists on the UK network?

Is it inherently dangerous given that this is the second time it has occurred at Kirkby?

Clearly not, because it is far, far safer than a conventional red signal with TPWS grids, which is what would otherwise have been there - compare it with, for example, platforms at Birmingham New St which have a mid-platform signal and two trains in each platform at once, or indeed with somewhere like Northampton which has permissive working (i.e. 2 trains in the same platform without a signal and overlap) for the purpose of joining portions.

Modern standards would not simply permit such a design to be newly installed today.

Wouldn't it? It's hardly much different from just having a signal there, or indeed being an end-on station concourse with buffers as found all over the country. OK, that would have a longer overlap, but then the buffer stops and concrete block provided some mitigation.

I can't see any reason why you couldn't do it now, albeit with heftier buffers and a slightly bigger gap to provide an overlap.

 

[Ianno87]

Clearly not, because it is far, far safer than a conventional red signal with TPWS grids, which is what would otherwise have been there - compare it with, for example, platforms at Birmingham New St which have a mid-platform signal and two trains in each platform at once, or indeed with somewhere like Northampton which has permissive working (i.e. 2 trains in the same platform without a signal and overlap) for the purpose of joining portions.

It could be argued that (in the historic design) safety risk has not been lowered "as far as reasonably practicable" as would be required today.

Wouldn't it? It's hardly much different from just having a signal there, or indeed being an end-on station concourse with buffers as found all over the country. OK, that would have a longer overlap, but then the buffer stops and concrete block provided some mitigation.

I can't see any reason why you couldn't do it now, albeit with heftier buffers and a slightly bigger gap to provide an overlap.

That's what I suspect will be the case at Headbolt Lane - tracks still end on, but a greater separation between the buffers (and between the buffers and passenger circulation areas), standbank from the buffers, not having a road bridge directly over the top, and frangible platforms rather than a lump of concrete. That would apply modern standards and mitigate the consequences of a running into the buffers.

 

[Bletchleyite]

It could be argued that (in the historic design) safety risk has not been lowered "as far as reasonably practicable" as would be required today.

That's an interesting point given that it would be perfectly allowed for it just to be one platform with a mid-platform signal and an overlap, which would arguably pose a higher risk.

It will be interesting to see the cause of this - I don't entirely understand why TPWS didn't stop it.

That's what I suspect will be the case at Headbolt Lane - tracks still end on, but a greater separation between the buffers (and between the buffers and passenger circulation areas), standbank from the buffers, not having a road bridge directly over the top, and frangible platforms rather than a lump of concrete. That would apply modern standards and mitigate the consequences of a running into the buffers.

I believe Headbolt Lane is going to be two platforms for Merseyrail (eventually through platforms) plus a (sort-of) bay for the DMU. I wonder if they will be connected through like Ellesmere Port is?

 

[Ianno87]

That's an interesting point given that it would be perfectly allowed for it just to be one platform with a mid-platform signal and an overlap, which would arguably pose a higher risk.

I wasn't necessarily thinking that - more sticking a few extra metres of platform at either end so that the buffers didn't have to be so close to the passenger walkway would strike me as the sort of "practicable" mitigation that would be applied today.

I believe Headbolt Lane is going to be two platforms for Merseyrail (eventually through platforms) plus a (sort-of) bay for the DMU. I wonder if they will be connected through like Ellesmere Port is?

From the Headbolt Lane thread, yes - but one Merseyrail platform and the DMU platform will have their tracks "end on" as at Kirkby (except that the platform face won't be on the same side of the track as each other) - but I'd presume with a greater separation distance between them than is applied at Kirkby.

 

[2HAP]

BBC Merseyside just posted a story at 13:31.

Kirkby station: Merseyrail investigating derailment

Twelve passengers and two crew were on board the Merseyrail service which derailed on Saturday.

www.bbc.co.uk

An investigation is under way after a train derailed when it hit a buffer stop.
Twelve passengers and two crew members were on board when the incident happened at Kirkby station at about 18:35 GMT on Saturday.
They were checked by paramedics at the scene and no further medical treatment was required, Merseyrail said.

 

[Bletchleyite]

I wasn't necessarily thinking that - more sticking a few extra metres of platform at either end so that the buffers didn't have to be so close to the passenger walkway would strike me as the sort of "practicable" mitigation that would be applied today.

Ah, yes, that makes sense - basically a longer "overlap", and probably better buffers, too. In essence I guess the arrangement isn't flawed, but the gap between the buffers and "stuff the unit could hit" (be that passengers on the walkway, or another unit) would be longer.

From the Headbolt Lane thread, yes - but one Merseyrail platform and the DMU platform will have their tracks "end on" as at Kirkby (except that the platform face won't be on the same side of the track as each other) - but I'd presume with a greater separation distance between them than is applied at Kirkby.

Yes, I'd expect so.

 

[Snow1964]

Clearly not, because it is far, far safer than a conventional red signal with TPWS grids, which is what would otherwise have been there - compare it with, for example, platforms at Birmingham New St which have a mid-platform signal and two trains in each platform at once, or indeed with somewhere like Northampton which has permissive working (i.e. 2 trains in the same platform without a signal and overlap) for the purpose of joining portions.



Wouldn't it? It's hardly much different from just having a signal there, or indeed being an end-on station concourse with buffers as found all over the country. OK, that would have a longer overlap, but then the buffer stops and concrete block provided some mitigation.

I can't see any reason why you couldn't do it now, albeit with heftier buffers and a slightly bigger gap to provide an overlap.

Odd situation to risk assess, could have overlap in front of buffers (so buffers only useful if ran through whole overlap), or no buffers (chance line beyond is empty).

But I suspect this is still acceptable (thinking of Clapham Junction platform 2 where buffers were added mid length, and a 5 car electric train needs to draw up fairly close to buffers to fully fit in platform)

 

[Ianno87]

But I suspect this is still acceptable (thinking of Clapham Junction platform 2 where buffers were added mid length, and a 5 car electric train needs to draw up fairly close to buffers to fully fit in platform)

The mitigation there is (IIRC) a 5mph crawl into the platform. Probably because there is no other "practicable" solution.

 

[Wezz]

The mitigation there is (IIRC) a 5mph crawl into the platform. Probably because there is no other "practicable" solution.

Kirkby has a slow approach speed, I think it's 10mph.

 

[D6130]

Kirkby has a slow approach speed, I think it's 10mph.

Initially perhaps.....but then you have to reduce to less than 5 mph to pass over the TPWS grid without causing an emergency brake application.

 

[Bletchleyite]

Initially perhaps.....but then you have to reduce to less than 5 mph to pass over the TPWS grid without causing an emergency brake application.

That doesn't overly look like a 5mph collision!

 

[507 001]

Kirkby has a slow approach speed, I think it's 10mph.

It’s 15 into the platform. Down from 60 for passenger trains. 20 over 60 between Fazakerley and Kirkby.

Odd situation to risk assess, could have overlap in front of buffers (so buffers only useful if ran through whole overlap), or no buffers (chance line beyond is empty).

But I suspect this is still acceptable (thinking of Clapham Junction platform 2 where buffers were added mid length, and a 5 car electric train needs to draw up fairly close to buffers to fully fit in platform)

After the 1997 incident 3 car trains did start stopping much further back from the buffer stop. 6 car sets still draw up quite close.

 

[Trackman]

That doesn't overly look like a 5mph collision!

I agree.
Google about the Sudbury buffer incident, a 156 hit the buffers (similar to the one at Kirkby) at I think about 7mph, causing minor damage to the unit and bent the buffers.
There it was 10mph for TPWS, let's say it's 15 at Kirkby (as just stated) I still think at lets say 13mph I don't think it would have caused so much damage and gone so far, I'm no expert, it's just how I see it.

 

[Llama]

Initially perhaps.....but then you have to reduce to less than 5 mph to pass over the TPWS grid without causing an emergency brake application.

It doesn't have to be less than 5mph at TPWS loops in bay platforms.

They'll most likely be miniature loops at a standard installation, normally 55m from the buffer stop, and drivers will be instructed to do 'less than 10' over the loops. Actual set-speed for passenger stock will be either 10mph or 13mph.

I'm fairly sure there will be a TPWS installation on approach to the 15mph PSR before the platform where permissible speed drops from 60mph for that stock.

There is however no equivalent PSR approaching from the Wigan direction, effectively being 70mph straight up to a buffer stop. There is no TPWS on the Wigan side apart from the miniature OSS loops in the platform set at 10mph 55m from the buffers.

 

[Bletchleyite]

I agree.bu
Google about the Sudbury buffer incident, a 156 hit the buffers (similar to the one at Kirkby) at I think about 7mph, causing minor damage to the unit and bent the buffers.
There it was 10mph for TPWS, let's say it's 15 at Kirkby (as just stated) I still think at lets say 13mph I don't think it would have caused so much damage and gone so far, I'm no expert, it's just how I see it.

Which unit type was it that had an issue with transition between the dynamic brake and friction braking, thus causing a buffer stop collision or two in the past?

 

[Dieseldriver]

Which unit type was it that had an issue with transition between the dynamic brake and friction braking, thus causing a buffer stop collision or two in the past?

Pendolinos IIRC

 

[Stigy]

I agree.
Google about the Sudbury buffer incident, a 156 hit the buffers (similar to the one at Kirkby) at I think about 7mph, causing minor damage to the unit and bent the buffers.
There it was 10mph for TPWS, let's say it's 15 at Kirkby (as just stated) I still think at lets say 13mph I don't think it would have caused so much damage and gone so far, I'm no expert, it's just how I see it.

It’s 15mph in to the platform, it doesn’t mean it’s 15mph at the grids. I appreciate they can be set at differing trigger speeds but I’ve not seen them at more than 10mph. I always do 7 or 8 to be sure, but they’re generally set between 10 and 12mph as far as I’m aware.

 

[dgl]

Of course of you had a case where the brakes had failed a TPWS application won't do anything apart from (I would guess) cut the traction power.

 

[507 001]

Let’s just theoretically say that the train hit the TPWS ramps at about 25 with the brake in Emergency. It isn’t going to stop before the blocks, regardless of what TPWS does...

It was raining quite heavily here (Huyton, not that far away) at the time. Kirkby is known for being slippery.

 

[Fincra5]

Of course of you had a case where the brakes had failed a TPWS application won't do anything apart from (I would guess) cut the traction power.

Exactly...

Let’s just theoretically say that the train hit the TPWS ramps at about 25 with the brake in Emergency. It isn’t going to stop before the blocks, regardless of what TPWS does...

It was raining quite heavily here (Huyton, not that far away) at the time. Kirkby is known for being slippery.

Indeed, if its sliding, with the brakes already in Emergency, TPWS will do nothing to slow the train down. The reports will show what happened, we could speculate for ages!

 

[Dieseldriver]

I do find it strange how many people reference TPWS when incidents such as these happen. TPWS is good but it’s not good enough to defy the laws of physics, it isn’t designed to prevent bufferstop collisions/SPADS/overspeeding, it’s designed to mitigate and try and lesson the consequences.
Also, with the best will in the world TPWS isn’t necessarily 100% failsafe, there could be a fault with the train bourne equipment or the track equipment.
Last but not least, it is permitted for a passenger train to run at 60mph with isolated TPWS as per the rule book.
TPWS is a great system and I’ve no doubt it’s prevented some quite nasty occurrences but we still rely heavily on human factors in running a safe railway.