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Failure to lower pantograph

Skimpot flyer

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Was just on a London Overground train from Willesden Junction to Clapham Junction when there was a loud bang near Shepherds Bush. After a long delay, we proceeded slowly into SPB, where the reason for the bang became obvious, as per the attached photo.
How can this happen? I thought these units switched from the overhead to the DC power automatically ?
 

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zwk500

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Fairly sure the automatic changeover equipment isn't fitted to track nor train on the Overground, so it will be manual selection only. Overground change on the move at this location, so if the driver is slow or doesn't see the sign (easily missable in the dark, especially if it's covered in graffiti or otherwise vandalised) for any reason then the overbridge can come up quick. GTR trains come to a stand (or almost) to avoid this problem.
 

Bald Rick

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Its not automatic.

Another one for the collection at pantograph corner.
 

43066

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Was just on a London Overground train from Willesden Junction to Clapham Junction when there was a loud bang near Shepherds Bush. After a long delay, we proceeded slowly into SPB, where the reason for the bang became obvious, as per the attached photo.
How can this happen? I thought these units switched from the overhead to the DC power automatically ?

Nope. Still done manually.

Its not automatic.

Another one for the collection at pantograph corner.

And a meeting sans biscuits for someone!
 

43066

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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".

Both are correct as the driver wouldn’t be able to continue after an incident like that, and (obviously) the train couldn’t continue either, even on the DC, until the damage had been thoroughly inspected.
 

Business Bob

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Both are correct as the driver wouldn’t be able to continue after an incident like that, and (obviously) the train couldn’t continue either, even on the DC, until the damage had been thoroughly inspected.
Driver been relived and train's been inspected, pan isolated... awaiting on NR now
 

TrainGeekUK

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Trains using a single line bi directional around the problem.
I’m a little surprised the Southern service wasn’t culled in the area though.
 

SECR263

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In view of the fact the drivers cannot be trusted to change over by themselves should there not be big flashing signs actually saying panto up, panto down. Or leaving terminal stations, have you got the right panto up.
 

Russel

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It's 2024, surly some kind of device or setting can be added to all trains fitted with 3rd rail gear and pantographs that triggers the pantograph to drop as soon as the train detects a current from the 3rd rail? Or even something that works by GPS and auto lowers the pantograph at certain locations?

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

TreacleMiller

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It's 2024, surly some kind of device or setting can be added to all trains fitted with 3rd rail gear and pantographs that triggers the pantograph to drop as soon as the train detects a current from the 3rd rail? Or even something that works by GPS and auto lowers the pantograph at certain locations?

After all, we were able to land humans on the surface of the moon over 50 years ago!
Apco Belise exist. Have done for years.
 

43066

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It's 2024, surly some kind of device or setting can be added to all trains fitted with 3rd rail gear and pantographs that triggers the pantograph to drop as soon as the train detects a current from the 3rd rail?

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.

Or even something that works by GPS and auto lowers the pantograph at certain locations?

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.

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

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.

Apco Belise exist. Have done for years.

Yes. Although there have been a few high profile examples of pans not being lowered when needed on GTR’s balise based system (admittedly usually in out of course situations where it has to be manually overridden), which shows no system is totally infallible.

At this location the powers that be have chosen to accept some additional risk by 1. Having an human error prone entirely manual system, and 2. electing to make the change on the move rather than when stationary.

(Should also say we don’t 100% know this particular incident was down to human error, albeit highly likely. It’s just possible he followed the procedure to the letter and the pan failed to drop, ADD malfunctioned etc.)
 
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Bald Rick

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Same could be said for Thameslink at Farringdon <> City Thameslink!

Much more popular at the A40.


In view of the fact the drivers cannot be trusted to change over by themselves should there not be big flashing signs actually saying panto up, panto down. Or leaving terminal stations, have you got the right panto up.

There is a big sign, albeit it doesn‘t flash.

There is something peculiar about this example, comapred to the many other locations now and historically where AC>DC voltage change occurs.
 

43066

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There is a big sign, albeit it doesn‘t flash.

There is something peculiar about this example, comapred to the many other locations now and historically where AC>DC voltage change occurs.

Not knowing the location, it would be interesting to know whether there is some additional distraction factor here e.g, are they more likely to be running on restrictive aspects, is there a speed change nearby etc.
 

zwk500

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It's 2024, surly some kind of device or setting can be added to all trains fitted with 3rd rail gear and pantographs that triggers the pantograph to drop as soon as the train detects a current from the 3rd rail? Or even something that works by GPS and auto lowers the pantograph at certain locations?
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!
After all, we were able to land humans on the surface of the moon over 50 years ago!
Not sure what relevance the Apollo programme has given the level of manual control in the spacecraft.
There is a big sign, albeit it doesn‘t flash.
Presumably one element that will be checked is whether the sign was in good order.
There is something peculiar about this example, comapred to the many other locations now and historically where AC>DC voltage change occurs.
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.
 

dk1

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Lucky we have COP (Change Over Protection) although that has failed to activate a couple of times over the years due to software issues.
 

Skimpot flyer

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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.



Yes. Although there have been a few high profile examples of pans not being lowered when needed on GTR’s balise based system (admittedly usually in out of course situations where it has to be manually overridden), which shows no system is totally infallible.

At this location the powers that be have chosen to accept some additional risk by 1. Having an human error prone entirely manual system, and 2. electing to make the change on the move rather than when stationary.

(Should also say we don’t 100% know this particular incident was down to human error, albeit highly likely. It’s just possible he followed the procedure to the letter and the pan failed to drop, ADD malfunctioned etc.)
The driver was a lady. She walked through the train looking for signs of damage. It was when we were told to alight at Shepherds Bush that the reason for the bang became apparent, to observant eyes !
 

norbitonflyer

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It's 2024, surly some kind of device or setting can be added to all trains fitted with 3rd rail gear and pantographs that triggers the pantograph to drop as soon as the train detects a current from the 3rd rail?
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.
 

Meerkat

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What distances are we talking here between the point that the driver needs to hit the button and the first thing they hit?
 

subria

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Not knowing the location, it would be interesting to know whether there is some additional distraction factor here e.g, are they more likely to be running on restrictive aspects, is there a speed change nearby etc.

https://www.google.com/maps/@51.5214446,-0.2311308,16.5z/data=!5m1!1e2?entry=ttu

The changeover generally happens while on the move between the GWML and the Westway road. The overhead wires stop around here and do not continue to Shepherd's Bush station. I recall a while back this was due to needing to deal with the Underground Circle Line passing overhead not long after this requiring extensive isolation work.

In contrast on the Richmond line, the changeover occurs at Acton Central station itself (although the wires continue south past that station for about a train length).

In the past they used to stop the 378s and do the changeover while stopped (still happens on occasion). The Class 92s when they operated on this route used to do this as well - though presume it was easier than stop/starting a heavy freight train.
 

Bald Rick

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I recall a while back this was due to needing to deal with the Underground Circle Line passing overhead not long after this requiring extensive isolation work.

In contrast on the Richmond line, the changeover occurs at Acton Central station itself (although the wires continue south past that station for about a train length).

There are some very curious electrical flows around both locstions, due presence of LU, 25kv, NR DC and all the linked lines.
 

swt_passenger

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What distances are we talking here between the point that the driver needs to hit the button and the first thing they hit?
It’s getting on for about 800m, or maybe more. The thread below, (back in November), covered the area in detail, includes links to videos in post #23. At line speeds I’d expect there’s going to be about 40 seconds between the first pan down warning and the A40 bridge. The third rail starts at Scrubs Lane road bridge, and the wires don’t run off to the side until almost at the A40 bridge.
 
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Lemmy99uk

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The driver was a lady. She walked through the train looking for signs of damage. It was when we were told to alight at Shepherds Bush that the reason for the bang became apparent, to observant eyes !

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

43066

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

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.
 

Sultan

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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?
 

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