Failure to lower pantograph

[choochoochoo]

I'm sure the technology exists - could an audible reminder be fitted in the cab (to lower the pan as a DC only section is approaching)?

The 313 used to have a dual voltage alarm when it was going from AC to DC to warn the driver they were getting both supplies.

 

[CarrotPie]

Sorry for my ignorance, but having travelled on this stretch of track on a number of occasions, is the 'bang' caused by connection to both AC and DC feeds at the same time or a raised pantograph striking a low bridge as the train travelled south towards Shepherds Bush?

The latter. I'm fairly Capitalstars can't connect to both at the same time - you have to put the pantograph down before you can lower the shoes - but I may be wrong on this.

 

[Lemmy99uk]

To be fair I think that poster was on the train, and I had (wrongly as it turns out!) assumed the driver was male in my earlier reply.

In which case, apologies for the knee-jerk reaction.

 

[Bald Rick]

Sorry for my ignorance, but having travelled on this stretch of track on a number of occasions, is the 'bang' caused by connection to both AC and DC feeds at the same time or a raised pantograph striking a low bridge as the train travelled south towards Shepherds Bush?

There is always a bang on changeover , as the AC circuit breaker opens and the pantograph drops with a clatter.

In the instance of the OPs expeirence in this post, the bang was, however, a rapid unscheduled detachment of pantograph from train.

 

[ExRes]

It's a few years ago now but when we had to raise or lower the shoes and pantograph on a 325 there were clear signs in both directions as a double check for anyone forgetting their basic route knowledge

 

[Russel]

It couldn’t be completely instant, though, as that would lead to an immediate cut of power to motors as soon as the collector shoes hit the juice rail in the overlap. There needs to be some additional system to actively prompt the pan to drop or rise at the point you need it to, and the on train systems to reconfigure.



How would a GPS system work in (say) the TL core? And would it be accurate enough? The alternative would likely be a balise based system.



And the systems and technology used to do that had failures, too! In the end there’s always some compromise between budget and design spec.

Needs to be more complicated than that or, when going the other way, the pantograph would be unable to rise until the train had left the juice rail.

Okay, so my suggestion was a little simplistic and only two suggestions off the top of my head, but there has to be a way of preventing this happening from happening.

Track side sensors that tell the train to drop the panto if it's still in the raised position?

It seems ridiculous that we are still reliant on trackside signs reminding the driver being the main way this is done...

 

[Purple Train]

Okay, so my suggestion was a little simplistic and only two suggestions off the top of my head, but there has to be a way of preventing this happening from happening.

Track side sensors that tell the train to drop the panto if it's still in the raised position?

It seems ridiculous that we are still reliant on trackside signs reminding the driver being the main way this is done...

I seem to recall we had a thread on this very subject not very long ago, after an incident at City Thameslink. My suggestion then was some kind of lightweight old-fashioned loading gauge (fairly obvious visual cue) which, if contacted by a pantograph, would trigger something fairly similar to the SPAD warning lights that were introduced to protect signals where the consequence of a SPAD was high, and bring the train safely to a stand, without the pantograph pretty much unscathed. Would there be a way of making sure a (what I take to be) relatively flimsy thing such as a pantograph can contact such an object without the system being activated by a gust of wind or a bird or something? Or would light gates work better than a physical object?

 

[Signal Head]

Given the number of briefings the ARL drivers get on this very subject, I suspect no tea either.

Bread and Water rations for a week!

 

[Rich1974]

Let's get one thing correct here, it doesn't make a difference what sex the driver is, we all make mistakes, we forget, we get distracted, sadly it's life, myself as a driver I've been lucky, one day my luck might run out, it doesn't mean I was trained badly or not a good driver it probably just means all the holes lined up on that day.

 

[GordonT]

Let's get one thing correct here, it doesn't make a difference what sex the driver is, we all make mistakes, we forget, we get distracted, sadly it's life, myself as a driver I've been lucky, one day my luck might run out, it doesn't mean I was trained badly or not a good driver it probably just means all the holes lined up on that day.

Good point but has it now been established beyond all doubt that the cause was entirely down to driver error and there were no equipment issues or other extenuating factors?

 

[Boodiggy]

Its not automatic.

Another one for the collection at pantograph corner.

Quite the collection now!

 

[Skimpot flyer]

I can think of no reason whatsoever why you would feel the need to mention the persons gender?

If you look at the entirety of my post (#21 in this thread), you’ll see I was correcting someone who referred to the driver as he…

 

[IanXC]

Service is this- 2Y13 1846 Stratford (London) to Clapham Junction https://www.realtimetrains.co.uk/service/gb-nr:L02584/2024-01-09/detailed
It's odd how RTT is condemning the traincrew already "due to an issue with the train crew (TG)" where TOPS says "M1 PANTO/AC CMEE" which is described as "Confirmed Pantograph ADD, shoe beam or associated system faults Incl. positive PANCHEX activations".

That would imply that when the service was initially terminated the Controllers attributed the issue to the Driver (for instance failing to lower the pan) whereas the attribution has subsequently been changed to the Pantograph - that suggests something akin to the driver acting correctly but the pan failing to lower due to a fault.

 

[Busaholic]

After all, we were able to land humans on the surface of the moon over 50 years ago!

But never since!

 

[Skimpot flyer]

<dons tin-foil hat>
Stanley Kubrick said he didn’t have the time or inclination to set-up the studio again…

 

[matthenj]

I seem to recall we had a thread on this very subject not very long ago, after an incident at City Thameslink. My suggestion then was some kind of lightweight old-fashioned loading gauge (fairly obvious visual cue) which, if contacted by a pantograph, would trigger something fairly similar to the SPAD warning lights that were introduced to protect signals where the consequence of a SPAD was high, and bring the train safely to a stand, without the pantograph pretty much unscathed. Would there be a way of making sure a (what I take to be) relatively flimsy thing such as a pantograph can contact such an object without the system being activated by a gust of wind or a bird or something? Or would light gates work better than a physical object?

Unnecessarily complicated. Camera linked to a signal is all that's required.

Teach a computer what a train with a pantograph up looks like, and if it sees one set a red aspect before the low bridge. Changes to green when the signaler confirms the pantograph is dropped.

The computer science is pretty well understood, and something like this could achieve a very high detection accuracy with few false positives.

No expensive unreliable line side detection lasers, trip wires etc required, just a plain old camera.

 

[Sly Old Fox]

Let's get one thing correct here, it doesn't make a difference what sex the driver is, we all make mistakes, we forget, we get distracted, sadly it's life, myself as a driver I've been lucky, one day my luck might run out, it doesn't mean I was trained badly or not a good driver it probably just means all the holes lined up on that day.

Nobody was suggesting otherwise.

 

[youngpete]

APCO is widely fitted on other lines. Here it is difficult because the trains may need additional modification to use it, there is a limited.length to change over, and you have the additional complexity (cost) of bidirectional lines. All solvable, but for a price. Given the number of failures per changes conducted, sending a memo out to drivers is much cheaper!

Not sure what relevance the Apollo programme has given the level of manual control in the spacecraft.

Presumably one element that will be checked is whether the sign was in good order.

Is this the last remaining transition between voltages on the fly? Eurostar no longer do, Javelin and Thameslink change in stations as does LO at South Acton while GTR come to a stand at a signal at this location.
APCO between diesel and AC or v.v. is obviously done on the fly but that has the advantage of switching to or from self power so can err on the side of safety with the pan.

Whilst Javelins normally reconfigure at stations when the Faversham to St Pancras run through Ebbsfleet non-stop they do reconfigure on the move.

 

[sharpener]

Given the expensive consequences of failure to get it right, a process like this in industry would be have been fully automated decades ago.

When I was a boy in the 50s I remember going to Earls Court where one of the exhibits was sorting all the black balls down one chute and the white balls down another, then re-forming them into groups of varying number. It required no more than relay ladder logic to implement. And not that long after we achieved full automatic train control on the Vic line.

So why does the railway make such heavy weather of what are relatively simple automation tasks? Is it to avoid perceived insults to members of ASLEF, or is it balkanisation of engineering expertise in the railway, or some other groupthink-like issue?

 

[Railsigns]

So why does the railway make such heavy weather of what are relatively simple automation tasks?

Because the consequences of getting it wrong are usually more serious than sorting the wrong colour of ball.

 

[Taunton]

I seem to recall we had a thread on this very subject not very long ago, after an incident at City Thameslink. My suggestion then was some kind of lightweight old-fashioned loading gauge (fairly obvious visual cue) which, if contacted by a pantograph, would trigger something fairly similar to the SPAD warning lights that were introduced to protect signals where the consequence of a SPAD was high, and bring the train safely to a stand, without the pantograph pretty much unscathed. Would there be a way of making sure a (what I take to be) relatively flimsy thing such as a pantograph can contact such an object without the system being activated by a gust of wind or a bird or something? Or would light gates work better than a physical object?

Simple electric switches in the overhead wire activated by a passing pantograph to do various tasks like operate points or trigger traffic lights have been a longstanding and completely reliable feature of tramways for the last 100 years now.

 

[Flying Snail]

Is there a reason that isolating the contact wire before the bridge and reducing the wire height, possibly using a fixed bar under the bridge, to force the pantograph to a clear height wouldn't work?

 

[Business Bob]

At Acton Central on the down, at the start of the platform just after the level crossing there is an APC magnet (Automatic Power Controller) that shuts off power to the pan. Usually found at neutral sections. So you have to select DC to continue. Also, changeover on the move is not authorised at Acton Central. Not sure how well an APC magnet would work on the bi-directional WLL at North Pole Jn.

 

[ptreanor]

APCO is widely fitted on other lines. Here it is difficult because the trains may need additional modification to use it, there is a limited.length to change over, and you have the additional complexity (cost) of bidirectional lines. All solvable, but for a price. Given the number of failures per changes conducted, sending a memo out to drivers is much cheaper!

Not sure what relevance the Apollo programme has given the level of manual control in the spacecraft.

Presumably one element that will be checked is whether the sign was in good order.

Is this the last remaining transition between voltages on the fly? Eurostar no longer do, Javelin and Thameslink change in stations as does LO at South Acton while GTR come to a stand at a signal at this location.
APCO between diesel and AC or v.v. is obviously done on the fly but that has the advantage of switching to or from self power so can err on the side of safety with the pan.

Eurostars change from 25kV HSL to 25kV ET (and vice versa) on the move nesr Westenhanger. This involves lowering and raising the pan. Similar process in France and in Belgium.

 

[dk1]

Pan protection on the 755 fleet will automatically bring us to a stand just before running out of wire. If doing it the official way and advising the signaller we just have to make it clear that it was not an ADD application therefore clearing things up that no allegation has been made against the OHL and there is no need to caution subsequent services or get the OHL examined.

 

[norbitonflyer]

Unnecessarily complicated. Camera linked to a signal is all that's required.

Teach a computer what a train with a pantograph up looks like, and if it sees one set a red aspect before the low bridge. Changes to green when the signaler confirms the pantograph is dropped.

That woukld work - if the distance of wiring beyond the camera was long enough for a train running at line speed to stop. (The wiring would have to continue at least as far as the red signal). In many of these incidents there is an overhead structure very shortly after the end of the wires.

 

[800301]

Pan protection on the 755 fleet will automatically bring us to a stand just before running out of wire. If doing it the official way and advising the signaller we just have to make it clear that it was not an ADD application therefore clearing things up that no allegation has been made against the OHL and there is no need to caution subsequent services or get the OHL examined.

Yet another nice feature on a lovely smart train that works and doesn't have a ridiculous maintenance contract attached to it...

 

[LBMPSB]

It needs someone to redesign the Automatic Drop Device (ADD) used on some pantographs that automatically drop the pan when it detects some sort of damage to the pan. I do not know how, but if someone could redesign ADD in such away that a sudden loss of pressure with the contact wire is detected, the ADD operates.

 

[najaB]

That woukld work - if the distance of wiring beyond the camera was long enough for a train running at line speed to stop. (The wiring would have to continue at least as far as the red signal). In many of these incidents there is an overhead structure very shortly after the end of the wires.

Surely that's fixed by moving the changeover point back a few train lengths, no?

It needs someone to redesign the Automatic Drop Device (ADD) used on some pantographs that automatically drop the pan when it detects some sort of damage to the pan. I do not know how, but if someone could redesign ADD in such away that a sudden loss of pressure with the contact wire is detected, the ADD operates.

Isn't that how over-height detection works?

 

[zwk500]

Teach a computer what a train with a pantograph up looks like, and if it sees one set a red aspect before the low bridge. Changes to green when the signaler confirms the pantograph is dropped.

1. Image recognition has had many failures in more controlled environments than this. The camera would need to be able to identify the pantograph in all weathers and lighting conditions, potentially with another train with a pantograph passing in the background.
2. Because of signal aspect sequences you would need to hold the signal at red before the train was within range of the camera. This defeats the objective of changing on the move.
3. This will increase routine signaller workload in a very busy area.