Thameslink Core pantograph strike

[QueensCurve]

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.

Do the sets not have an interlock to prevent DC power systems from being energised unless the pantograph is detected as fully down? If not, why not?

 

[aleggatta]

lets be honest, should there be a protection system? yes. is there likely going to be one? probably not. If I were to do one, I'd simply have a wire parallel to the run off wire, that would create a circuit to be completed by the bridging the wires with the carbons of the pan and trigger a REC call in the core. it's ridiculous that in the times of the Thameslink programme we didn't have DC extended to outside the core, in a location with a spare platform to allow overtaking following a failed changeover (or AC south to Blackfriars and all 4 platforms as through platforms).

 

[AM9]

lets be honest, should there be a protection system? yes. is there likely going to be one? probably not. If I were to do one, I'd simply have a wire parallel to the run off wire, that would create a circuit to be completed by the bridging the wires with the carbons of the pan and trigger a REC call in the core. it's ridiculous that in the times of the Thameslink programme we didn't have DC extended to outside the core, in a location with a spare platform to allow overtaking following a failed changeover (or AC south to Blackfriars and all 4 platforms as through platforms).

That's some capital expenditure just to help prevent what are comparatively infrequent hiccups,. It's not as if there is a h&s issue to fix, - just some inconvenient delays.

 

[uglymonkey]

Agree, but it screws over the Thameslink network for a day when it happens, costing a fair chunk each time ( never mind the inconvenience each time)

 

[jamieP]

Presumably if the train was in ATO it would stop at every station or if its setup as a Class 5 does it override station stops?

Class 5s are booked to stop so to do a power change over.

 

[Nicholas Lewis]

Class 5s are booked to stop so to do a power change over.

Understand that is what was required but question is if an ECS is running in ATO presumably it doesnt have station stops programmed in so a driver could just sit back and let ATO manage the train and thus easy its possible for a memory lapse that the driver has to intervene at at Farringdon to stop and do the traction c/o. If that is the case then they need to programme in a forced stop at Farringdon. I certainly know that on a Sunday Northbound trains still stop at City TL and dont open doors not sure how thats achieved unless they ahve drive on manual on a Sunday?

 

[jamieP]

Understand that is what was required but question is if an ECS is running in ATO presumably it doesnt have station stops programmed in so a driver could just sit back and let ATO manage the train and thus easy its possible for a memory lapse that the driver has to intervene at at Farringdon to stop and do the traction c/o. If that is the case then they need to programme in a forced stop at Farringdon. I certainly know that on a Sunday Northbound trains still stop at City TL and dont open doors not sure how thats achieved unless they ahve drive on manual on a Sunday?

I might be wrong but my understanding with ATO is it only works if the train has a schedule which this did and if in ATO the driver should not need to intervene as it will follow the schedule. Same as it would in passenger service.

 

[AM9]

Agree, but it screws over the Thameslink network for a day when it happens, costing a fair chunk each time ( never mind the inconvenience each time)

I was alluding to the cost of @aleggatta 's ideas of DC or ac being extended through the core to the opposite side of the core where a bypass platform is established. That is in addition to a new rigged detection device and REC call mechanism. That would not be at a trivial cost, compared to many lost half days of normal operation, (which at the current low incudent rate would probably takeo 30+ years before such an investment was just breaking even). I doubt there is any appetite for that sort of belt and braces without a push on safety grounds.

 

[ThameslinkUser]

current low incident rate

Whilst the incident rate may be low, the severity of any such incident majorly affecting multiple regions with long-distance implications will surely result in a high cost that will be recouped rather quickly through such an investment.

 

[AM9]

Whilst the incident rate may be low, the severity of any such incident majorly affecting multiple regions with long-distance implications will surely result in a high cost that will be recouped rather quickly through such an investment.

I doubt that the impact bothers the railway much in its current malaise. It's not as if there aren't any alternative modes for travelling across the core, and the ripple out along the branches of TL might impede GTRs services, but other mainline services are far more frequenly delayed by other mishaps.

 

[Samzino]

I doubt that the impact bothers the railway much in its current malaise. It's not as if there aren't any alternative modes for travelling across the core, and the ripple out along the branches of TL might impede GTRs services, but other mainline services are far more frequenly delayed by other mishaps.

Has quite an effect especially on Kent bound Rainham services which are very much needed to stem the flow of passengers from the Elizabeth line at ABW towards Kent.

Just have to see how a one cancelled Rainham service in the evening peak definitely bothers that side of the railway.

 

[boiledbeans2]

Again, fair points, but signals already are used for other purposes - for example to hold a train for any number of reasons where proceeding would be wrong. The reasons for not entering a section are not just because of points - they include obstructions on the line, for example, which could be taken to include a pantograph not lowered, and therefore likely to cause an obstruction - in other words, the route is not properly set or available until the pan is down. I am not necessarily wedded to using signals for panto purposes, BTW, but it could be the method that involves the least additional equipment and complication.

For LU, if I understand, there is something called speed controlled signals? It forces a LU driver to reduce his/her speed to a pre-determined level before the signal clears. For the Thameslink case, the pre-determined speed could be set to zero.

 

[Deepgreen]

Out of interest what happens to a driver who forgets the panto? Does it involve extra training, a disciplinary hearing, etc? I'm wondering how it compares to a SPAD, for example.

Not sure it is. It is to compensate passengers who have been inconvenienced. Controllers, signallers and drivers don't make decisions on trying to get a train less than 15 minutes late, rather make decisions so that overall the service goes back to normal and leads to a reduction in overall delay & inconvenience.

'Delay Repay' is, I believe, simply a mechanism to make passengers think that the railway is being 'customer-friendly' when things go wrong. Its financial impact on TOCs is probably fairly minor, and allows them to get away with things that otherwise might involve greater investment spending (increased maintenance, rolling stock hire, etc.). It was a political move as part of the effort to shore up the privatised and disparate system. Just my view...

 

[AM9]

Out of interest what happens to a driver who forgets the panto? Does it involve extra training, a disciplinary hearing, etc? I'm wondering how it compares to a SPAD, for example.


'Delay Repay' is, I believe, simply a mechanism to make passengers think that the railway is being 'customer-friendly' when things go wrong. Its financial impact on TOCs is probably fairly minor, and allows them to get away with things that otherwise might involve greater investment spending (increased maintenance, rolling stock hire, etc.). It was a political move as part of the effort to shore up the privatised and disparate system. Just my view...

I would agree which is why I'm intimating that nothing much will be done about spending not inconsiderable sums to achieve absolute prevention of an infrequent issue. Were it the case that there was a significant possibility of injury to either staff of the public, there would be a case, but as it is Delay Repay means that no action is required to assuage inconvenienced passengers. GTR still gets paid for running the services.

 

[Deepgreen]

I would agree which is why I'm intimating that nothing much will be done about spending not inconsiderable sums to achieve absolute prevention of an infrequent issue. Were it the case that there was a significant possibility of injury to either staff of the public, there would be a case, but as it is Delay Repay means that no action is required to assuage inconvenienced passengers. GTR still gets paid for running the services.

I agree, however, from a service provision perspective (leaving aside finances), including the railway's reputation and reliability in the public's mind, perhaps the occasional issue like this is worth spending some money on? If it has been three incidents this year, and the 'familiarity breeds contempt' principle applies, then perhaps we may expect more to come? I really don't know, but would a technical solution really be beyond affordability? Perhaps it simply is an issue that is lived with, but on a modern railway, as a layman/passenger, I would expect some form of fail-safe device to be used - i.e. passenger mutterings along the lines of; "surely they can't just rely on people to make sure this happens?".

 

[norbitonflyer]

It is also a very public location - the results of any pantograph strike will be visible from Blackfriars station (and probably City TL as well) and from Queen Victoria Street, which is a busy City throughfare.

 

[class717]

As elsewhere, there has been considerable expenditure on bi-di signalling, which it then turns out is unable to be used to advantage because both there needs to be staff dealing with the issue, so no trains are now allowed to run on the opposite line, and also almost all the crossovers have been removed to save the track engineering budget, thus trains can't work around any issue anyway.

In case we think this approach is confined to rail, the road Blackwall Tunnel nearby had a multi-million makeover of its emergency signalling to use just one of the pair of tunnels for two-way traffic when the other was closed for works or an accident, and at the conclusion of the expenditure a separate department decided it was unsafe to have two way traffic in one tunnel (which had been done ever since the two were completed), so it has never been used as intended.

For a while trains were routed using the “wrong line” but to get the equipment to remove the pantograph up the side of the train, a line block was needed on both lines as there is no space for such equipment on the cess.

They can only take power from one at once, the train had enough run up from CTK to make it to where it was on no power after the OLE ended

Do the sets not have an interlock to prevent DC power systems from being energised unless the pantograph is detected as fully down? If not, why not?

Understand that is what was required but question is if an ECS is running in ATO presumably it doesnt have station stops programmed in so a driver could just sit back and let ATO manage the train and thus easy its possible for a memory lapse that the driver has to intervene at at Farringdon to stop and do the traction c/o. If that is the case then they need to programme in a forced stop at Farringdon. I certainly know that on a Sunday Northbound trains still stop at City TL and dont open doors not sure how thats achieved unless they ahve drive on manual on a Sunday?

The core is driven manually on weekends to retain competency.

 

[Bald Rick]

As elsewhere, there has been considerable expenditure on bi-di signalling, which it then turns out is unable to be used to advantage because both there needs to be staff dealing with the issue, so no trains are now allowed to run on the opposite line, and also almost all the crossovers have been removed to save the track engineering budget, thus trains can't work around any issue anyway.

The bidi was used, as mentioned above. and there are now more (and more useful) crossovers in the core than before the Thameslink Programme was done.

It is also a very public location - the results of any pantograph strike will be visible from Blackfriars station (and probably City TL as well) and from Queen Victoria Street, which is a busy City throughfare.

Not to mention giving a good belt to the NR offices!

 

[QueensCurve]

The bidi was used, as mentioned above. and there are now more (and more useful) crossovers in the core than before the Thameslink Programme was done.

The Thamelink core and the Castlefield curve both have bidirectional signalling where it can't be used without dramatic reductions to the service whereas other places, where it could be used to prevent serious service dispruption without causing much disruption in its own right, such as the northern half of the West Coast Main Line don't have it.

The core is driven manually on weekends to retain competency.

Doesn't really answer my point that the traction changeover to DC should not be possible without pantograph retraction. This is basic engineering without having to put any major modifiations in to the track or signalling. For example the Eurostar trains as built could not engage AC power without the shoegear detected as being fully retracted. I was personally on a train from London to Paris which was delayed 75 minutes at Dollands Moor due to a failure of shoegear detection but it prevented the train going into the Chunnel out of gauge.

 

[Nicholas Lewis]

Doesn't really answer my point that the traction changeover to DC should not be possible without pantograph retraction. This is basic engineering without having to put any major modifiations in to the track or signalling. For example the Eurostar trains as built could not engage AC power without the shoegear detected as being fully retracted. I was personally on a train from London to Paris which was delayed 75 minutes at Dollands Moor due to a failure of shoegear detection but it prevented the train going into the Chunnel out of gauge.

According to comments above it was running on 25kV never stopped to swap to DC. The deeper issue is why the ADD didn't drop the pan unless there just wasn't sufficent time from exiting city thameslink before the building at Blackfriars.

 

[Bald Rick]

The Thamelink core and the Castlefield curve both have bidirectional signalling where it can't be used without dramatic reductions to the service whereas other places, where it could be used to prevent serious service dispruption without causing much disruption in its own right, such as the northern half of the West Coast Main Line don't have it.

The Thameslink core is about 4 miles long. The northern half of the WCML nearly 200. A slight difference in cost! But be assured that were bidi be installed on the WCML north, Its use would not prevent serious disruption and service reductions. (Accepting that the disruption would be less than the cirrent position).

 

[swt_passenger]

… The deeper issue is why the ADD didn't drop the pan unless there just wasn't sufficent time from exiting city thameslink before the building at Blackfriars.

That’s been the explanation in earlier threads, IIRC. It’s only just over 100m.

 

[Bald Rick]

That’s been the explanation in earlier threads, IIRC. It’s only just over 100m.

Which at 30mph is about 8 seconds.

 

[Nicholas Lewis]

Which at 30mph is about 8 seconds.

A loco pan used to get to full height in 3-4 seconds from parked position this pan was already up so would already be exerting upward pressure on the wires so would be expected to react quicker. Shame we don't get to see the outcome of cause from these big incidents as still feels like an ADD failure.

 

[jdp30]

When the pan is dropped at Farringdon, doesn't seem to take more than a second or so to drop down? I'm pretty sure it's usually down before the doors even open?

 

[AM9]

When the pan is dropped at Farringdon, doesn't seem to take more than a second or so to drop down? I'm pretty sure it's usually down before the doors even open?

There's a world of difference between a pantograph dropping from a normal working range height (which at Farringdon and City Thameslink is quite low), in response to a command and the process of a working pantograph rising at a controlled rate, hitting a limit sensor, and then falling from fully extended to rest which owing to the height might be speed limited to prevent damage to the mechanism.

 

[Falcon1200]

But be assured that were bidi be installed on the WCML north, Its use would not prevent serious disruption and service reductions. (Accepting that the disruption would be less than the cirrent position).

Disruption certainly, but far, far less than at present; A major issue with the northern WCML (the Scottish part of which was for some time part of my area as a NR Controller) is the time taken to get staff to site for Single Line Working; Depending on the section up to four staff are required, and it was not uncommon for it to take two hours to get them there, during which time everything on the affected line stood.

 

[Bald Rick]

Disruption certainly, but far, far less than at present; A major issue with the northern WCML (the Scottish part of which was for some time part of my area as a NR Controller) is the time taken to get staff to site for Single Line Working; Depending on the section up to four staff are required, and it was not uncommon for it to take two hours to get them there, during which time everything on the affected line stood.

Oh I know. same in my experience.

My point is that with the quantity of traffic on the line now, having bidi means that at least half of it would have to be cancelled, especially with the amount of long freights around. And on the basis that its pretty difficult to cancel a freight that’s already rolling, some pretty long waits will be in order anyway.

 

[Taunton]

Oh I know. same in my experience.

My point is that with the quantity of traffic on the line now, having bidi means that at least half of it would have to be cancelled, especially with the amount of long freights around. And on the basis that its pretty difficult to cancel a freight that’s already rolling, some pretty long waits will be in order anyway.

Well it depends of course on how long the sections are. If you want to compare going over Shap with the Gotthard, the latter, long before the new tunnel, seemed to have double crossovers at least every couple of miles, often more frequent, and looking at the tracks they seemed well used. Likewise the Moscow Metro, dug in separate single line tunnels, seems to have scissors crossovers at most stations, sometimes at both ends.

 

[Bald Rick]

Well it depends of course on how long the sections are. If you want to compare going over Shap with the Gotthard, the latter, long before the new tunnel, seemed to have double crossovers at least every couple of miles, often more frequent, and looking at the tracks they seemed well used. Likewise the Moscow Metro, dug in separate single line tunnels, seems to have scissors crossovers at most stations, sometimes at both ends.

Back on topic, and as we see on Thameslink, with 4 (and a half) sets of crossovers in less than three miles from just north of St Pancras to Blackfriars South, it can sustain at best a quarter if the normal service if one section is out and even that will incur delays.