Thameslink Core pantograph strike

[londonmidland]

Currently at St. Pancras low level and at the time of posting, all Thameslink services have been suspended due to a pantograph on a 700 not being lowered within the core, which has subsequently damaged it.

All lines are blocked whilst inspections take place.

 

[uglymonkey]

I thought the pantograph up down was at Farringdon always? ( to switch to 3rd rail)

 

[DelW]

I thought the pantograph up down was at Farringdon always? ( to switch to 3rd rail)

OP only said that they were at St Pancras, not that the incident was there.

 

[Snow1964]

I thought they extended to wire overlap to City Thameslink few years ago, so that if Farringdon was closed trains could change nearby

 

[londonmidland]

The affected train is 5K15, which is stuck outside of London Blackfriars.

 

[ar10642]

I thought the pantograph up down was at Farringdon always? ( to switch to 3rd rail)

Going north they usually raise pantograph at City Thameslink, going south they usually lower the pantograph at Farringdon.

 

[45107]

The affected train is 5K15, which is stuck outside of London Blackfriars.

And, from personal observation, has been stood there since approx 1000 this morning

 

[Peter Mugridge]

Given the number of times this has happened now, would it not be an idea to put a neutral section of the overhead in as far as Blackfriars?

Granted, that wouldn't completely stop something being struck further down but the risk would be much lessened as, once clear of the roof at Blackfriars, it's some way to the first signal gantry and at the relatively slow speed from starting away wouldn't the automatic drop detection have a greater chance of kicking in before any damage is done?

 

[Future]

Thameslink core back open now after around four and a half hours of being completely shut! Apparently the panto had to be physically removed from the 700.

 

[AM9]

Given the number of times this has happened now, would it not be an idea to put a neutral section of the overhead in as far as Blackfriars?

Granted, that wouldn't completely stop something being struck further down but the risk would be much lessened as, once clear of the roof at Blackfriars, it's some way to the first signal gantry and at the relatively slow speed from starting away wouldn't the automatic drop detection have a greater chance of kicking in before any damage is done?

Plus the fact that is is an incline of 1:27 (or 1:29) up to Blackfriars which without power would cause the train to slow to a halt pretty quickly.

 

[Samzino]

It happens rarely so I doubt the logistics of a neutral section or adaptation to avoid such an incident repeating will be considered by the company if the cost doesn't warrant it. As said above a neutral section may reduce the incident happening again but may also lead to more issues like a train halting on the incline and panicking customers egressing (for example of extremes).

 

[Peter Mugridge]

Plus the fact that is is an incline of 1:27 (or 1:29) up to Blackfriars which without power would cause the train to slow to a halt pretty quickly.

It happens rarely so I doubt the logistics of a neutral section or adaptation to avoid such an incident repeating will be considered by the company if the cost doesn't warrant it. As said above a neutral section may reduce the incident happening again but may also lead to more issues like a train halting on the incline and panicking customers egressing (for example of extremes).

Are the trains not collecting third rail power when this happens, otherwise they would stop on the incline before the pantograph strikes anything anyway?

With a neutral section into Blackfriars, and rogue raised pantograph would be beyond the station and less likely to strike anything in the first place. It would also be possible to instruct staff to check if a pantograph is raised or not while in Blackfriars and thus increase the chances of preventing an incident.

How rarely is "it happens rarely" given that we seem to have something like this reported every few months? It's not just the cost of the physical damage to take into consideration - there's also the disruption claims and charges plus lost revenue from the disruption itself. How much would it actually cost to install such a neutral section?

 

[haltendehand]

Line reopened at 14.23 in both directions. Pantograph on 5K15 was damaged, apparently by hitting the office building over the line at Puddle Dock.

 

[Samzino]

Maybe im missing the point or not experienced but doesn't the Neutral section still rely on the driver going pan down at the appropriate time to traverse? As if so then unless it was a mechanical fault etc would that still mean if a driver forgets to do so that the Panto still ends up striking the Low roof at London Blackfriars anyway?

 

[father_jack]

Looks like 9K15 ex Luton was cancelled due to a fault, ran as 5K15 and only one pan out of two lowered........... Post amended due to duff gen corrected later

 

[jfollows]

Maybe im missing the point or not experienced but doesn't the Neutral section still rely on the driver going pan down at the appropriate time to traverse? As if so then unless it was a mechanical fault etc would that still mean if a driver forgets to do so that the Panto still ends up striking the Low roof at London Blackfriars anyway?

Pantographs don't drop for neutral sections, if that's what you think (https://www.railforums.co.uk/threads/overhead-neutral-sections-ohns.96414/).
(The very first issue of RAIL Magazine went on about a Class 87 cab ride and the pantograph dropping for neutral sections, which showed how bad it was, but perhaps it's a common misapprehension.)
I think Peter Mugridge means a section of wire which isn't energised, or something like that, rather than the normal meaning of a "neutral section" anyway.

EDIT See also http://ocs4rail.com/

 

[Peter Mugridge]

I think Peter Mugridge means a section of wire which isn't energised, or something like that, rather than the normal meaning of a "neutral section" anyway.

Correct - I am suggesting a long neutral section from the end of the present overheads into the full length of Blackfriars station for the sole purpose of preventing any defective or forgotten pantograph from rising and striking the buildings between City and Blackfriars.

If one does happen, it would be visually obvious to any staff in the form of a raised pantograph at Blackfriars and if it still isn't spotted and the driver alerted at that point, any continued raising would happen beyond the station and hopefully the automatic drop detection would have time to react before it hit any of the signal gantries beyond the station.

 

[Samzino]

Pantographs don't drop for neutral sections, if that's what you think (https://www.railforums.co.uk/threads/overhead-neutral-sections-ohns.96414/).
(The very first issue of RAIL Magazine went on about a Class 87 cab ride and the pantograph dropping for neutral sections, which showed how bad it was, but perhaps it's a common misapprehension.)
I think Peter Mugridge means a section of wire which isn't energised, or something like that, rather than the normal meaning of a "neutral section" anyway.

EDIT See also http://ocs4rail.com/

Understood but one is assuming the automatic drop detection won't fail if a panto raises before an energized overhead appears

 

[Peter Mugridge]

Understood but one is assuming the automatic drop detection won't fail if a panto raises before an energized overhead appears

It could of course fail, but it would be far easier for staff - especially if instructed to watch out for raised pantographs - to spot an issue at Blackfriars ( with the bright high roof ) than at City Thameslink ( which has a rather dark New Street like roof area ) and hopefully prevent the train leaving until it's been sorted.

 

[Samzino]

It could of course fail, but it would be far easier for staff - especially if instructed to watch out for raised pantographs - to spot an issue at Blackfriars ( with the bright high roof ) than at City Thameslink ( which has a rather dark New Street like roof area ) and hopefully prevent the train leaving until it's been sorted.

That is true indeed. I see.

 

[Peter Mugridge]

One thing I should ask - how far south of Blackfriars is the first signal gantry that a pantograph could foul should the issue not be spotted at Blackfriars, and could it easily be protected against a strike?

The key point there is not to risk creating a worse situation by possibly knocking out miles of signalling... The idea of the neutral section into Blackfriars is obviously to reduce the risk of disruption and not create worse disruption.

 

[Purple Train]

Pantographs don't drop for neutral sections, if that's what you think (https://www.railforums.co.uk/threads/overhead-neutral-sections-ohns.96414/).
(The very first issue of RAIL Magazine went on about a Class 87 cab ride and the pantograph dropping for neutral sections, which showed how bad it was, but perhaps it's a common misapprehension.)
I think Peter Mugridge means a section of wire which isn't energised, or something like that, rather than the normal meaning of a "neutral section" anyway.

EDIT See also http://ocs4rail.com/

(Third issue of Rail Magazine I think. I have it somewhere...)

What about just having a manual loading gauge (à la steam days) at each end that doesn't cause as much damage?

 

[Peter Mugridge]

What about just having a manual loading gauge (à la steam days) at each end that doesn't cause as much damage?

That's a good thought... you'd only need it at the south end, though - to catch anything not spotted before departure from Blackfriars.

I've just looked at Google Streetview and answered my own question about the gantries; there's enough of them that you'd have to otherwise continue the neutral section down to Warden's Grove towards London bridge and as far as Flying fantastic on the Elephant route. That's starting to get a bit far, and a loading gauge at Blackfriars would do the job ( perhaps placed past the first gantry, so the neutral section as far as the first gantry - roughly where I've drawn the dotted line on the screenshot below - solid line would be the extent of the neutral section ).

 

[Somewhere]

It happens rarely so I doubt the logistics of a neutral section or adaptation to avoid such an incident repeating will be considered by the company if the cost doesn't warrant it. As said above a neutral section may reduce the incident happening again but may also lead to more issues like a train halting on the incline and panicking customers egressing (for example of extremes).

Its not that rarely. Is it three times in the last year? And considering it causes mass disruption across five regions (Sussex, Kent, Derby, York and Anglia) when it does happen, something needs to help prevent it

 

[ThameslinkUser]

What is the possibility of having a pantograph detector linked to the signalling system? If train sets off, pantograph hits a detector (similar to surface stock detectors on LU) then ETCS movement authority is set to 0 or some such similar thing.

 

[norbitonflyer]

You don't need a physical loading gauge. Just a light and a photocell on opposite sides of the track, above the level of the cariage roofs, at t a height that would be obstructed by a raised pantograph. Anything breaking the beam causes the signal at the end of the platform to stay red. (You might need two, to avoid accidental triggering by pigeons).

 

[bahnause]

ETCS has a function to lower pantographs (if implemented).

 

[Deepgreen]

What is the possibility of having a pantograph detector linked to the signalling system? If train sets off, pantograph hits a detector (similar to surface stock detectors on LU) then ETCS movement authority is set to 0 or some such similar thing.

My thoughts exactly - can't be a difficult or expensive thing to have an alarm sound in the cab or similar from something like a movement sensor at the right height. I'm surprised it wasn't installed from the outset. However, what I haven't seen mentioned yet is whether it was human error (not lowering) or mechanical failure (lowering activated but failed on one pantograph).

 

[uglymonkey]

It needs to be "fail safe" somehow in case of human error surely? Like releasing the deadmans ( persons) handle. At the moment it's not and errors do happen. It's such a vital core route, especially on the 2 track central "core" (hate that word), that just to rely on human frailty to push or release a button for the " up and down" is a hostage to "forget". This is supposed to be the 21st Centry after all.

 

[TurboMan]

Given the number of times this has happened now, would it not be an idea to put a neutral section of the overhead in as far as Blackfriars?

Granted, that wouldn't completely stop something being struck further down but the risk would be much lessened as, once clear of the roof at Blackfriars, it's some way to the first signal gantry and at the relatively slow speed from starting away wouldn't the automatic drop detection have a greater chance of kicking in before any damage is done?

Sorry to be a pedant, but neutral section isn't the right term here. A neutral section is provided to prevent a phase-to-phase fault due to the train's pantograph bridging the gap between two separate electrical feeds which are out of phase. I think what you're thinking of is a de-energised run-off, where the pan runs onto a dead section of contact wire, the height of which gradually increases until the pantograph overheights and is lowered back into the pan well (this is not the same as an auto drop device (ADD) activation which detects damage to pantograph carbons).

ETCS has a function to lower pantographs (if implemented).

As on the GWML, where zero balises lower the pantograph before the end of the wire if the driver forgets to switch from electric to diesel.