378 De-Pantographed at Olympia

[Deepgreen]

Service suspended between Willesden Junction and Clapham Junction owing to a failed train - 378230 lost its pantograph quite spectacularly somewhere north of Kensington Olympia - on site repairs (presumably just to allow the train to be moved) under way - see photo.

 

[MylesHSG]

I thought it was 3rd rail down that stretch?

 

[PermitToTravel]

Yep, I believe that's why it lost its pantograph

 

[MylesHSG]

Ah, quite. Need another cup of coffee I think!

 

[Nippy]

Hmm, what's the betting that the driver forgot to lower the pan at North Pole then?

 

[Domh245]

Hmm, what's the betting that the driver forgot to lower the pan at North Pole then?

I'd have thought that the train would have either had an overheight alarm go off as it ran off the wires which should have raised the drivers attention, or the pantograph would have hit one of the bridges between North Pole and Shepherds Bush (or Olympia). I suspect that it was a spurious raising of the pantograph, but whether that was down to driver error or some fault of the train will have to be seen

 

[class 9]

Hmm, what's the betting that the driver forgot to lower the pan at North Pole then?

Nice pop at a driver there, electric traction has an ADD, auto dropping device, to stop the pan staying up when there are no wires.

 

[gsnedders]

Nice pop at a driver there, electric traction has an ADD, auto dropping device, to stop the pan staying up when there are no wires.

From memory some of the ADDs drop the pantograph so hard down into the well from full extension that it can damage the pantograph.

 

[Blamethrower]

Nice pop at a driver there, electric traction has an ADD, auto dropping device, to stop the pan staying up when there are no wires.

If that's true then why is there a massive sign at the south end of Farringdon reminding drivers to drop the pantograph?

 

[swt_passenger]

If that's true then why is there a massive sign at the south end of Farringdon reminding drivers to drop the pantograph?

Good question, given that although southbound changeovers normally take place at Farrngdon, the wires now terminate just south of City Thameslink...

 

[ComUtoR]

We suffered many pantograph crashes and we have an ADD.

I don't think Nippy was having a pop at the Driver. It's pretty common and usually Driver error.

My first thought was the Driver forgot to drop the pant.

 

[talltim]

But, but, but, they aren't wearing full orange!
--- old post above --- --- new post below ---

Nice pop at a driver there, electric traction has an ADD, auto dropping device, to stop the pan staying up when there are no wires.

So how did it hit anything then?

 

[ComUtoR]

Nice pop at a driver there, electric traction has an ADD, auto dropping device, to stop the pan staying up when there are no wires.

http://metro.co.uk/2014/01/02/trains-pantograph-crashes-into-roof-at-blackfriars-station-4247237/

The apparatus seems to have not been lowered at Farringdon station before it went straight into the ceiling at Blackfriars on Thursday morning.

The train was the 8:58am southbound service from St Albans to Sevenoaks.

319's have an ADD yet this still happened. There is a considerable distance between City and Blackfriars where the pan would be without wires.

Considering it would have been going about 20mph at the time the ADD would have had plenty of time to activate. Maybe there is a delay for it to work or maybe that the pan must reach a certain height before it drops. The gradient is quite severe and possibly that prevents the pan from going "over height"

 

[Lockwood]

Are there services that run between Farringdon, City Thameslink, Blackfriars and Olympia?

I thought that LO didn't venture near the Thameslink tunnel, so surely an ADD there or not there wouldn't have any effect here?

 

[61653 HTAFC]

If the ADD is there as a last resort, the sign will be there to prevent it being needed- especially if the pan being dropped from full height can cause damage.

 

[Deepgreen]

Whatever 378230's pantograph hit it was very solid, as there was little left other than a stump of the arm when I saw it at Olympia. If bridge/other structure strikes are an issue I would have thought it would be quite cheap to install deflecting inverted ramps at these places to force the pantograph down and avoid a collision, somewhat like the old steam exhaust deflectors fitted to over-bridges in days of yore to protect people on the bridges from exhaust blast, but of a shallower-angled and smooth finish design.

 

[Nippy]

I wasn't having a pop, just stating what I thought had happened based on 23 years of railway operational experience. Before the ADD activates the Pan will still go up and probably break. It isn't really there in case the driver forgets to lower it.

 

[westcoaster]

Think people are getting confused about what an ADD is. The ADD feature is if the pan receives damage, I.e carbon strips damaged releasing the air pressure, and dropping the pan.

If the driver forgets to lower it it should spring up, and drop down due to being overheight. Or what can happen sometimes it springs up and snaps its back. And falls in a broken heap.

 

[Stampy]

I'm no expert, but...

Might it have "dropped" as it should at the changeover to DC, but not "locked" down, and worked it's way loose???

 

[Bald Rick]

A regular occurrence, and the pans almost always come to grief on the Westway Bridge. Every incident I am aware of there has been due to the driver forgetting to drop the pan, and I'd be surprised if this wasn't.

If the pan is not dropped, when it runs off the wire it slowly rises until it reaches its overheight limit, at which point if then drops. This all takes time. More time than it takes to get from the end of the wire to Westway.

Re the City TL changeover; if a pan is left up if will stay on the wire until it has left City TL southbound. The same then happens: pan rises to the overheight limit and then drops back. Depending how fast the train is accelerating, it might just get to the office block (Puddledock) and clout it.

 

[SpacePhoenix]

Could the same system used on the 700s to auto raise/lower the pan be retrofitted on LO units?

 

[tim_lathe]

Maybe these trains require a system whereby if the train senses a live 3rd rail under it, down comes the pantograph by itself.

 

[Bald Rick]

Maybe these trains require a system whereby if the train senses a live 3rd rail under it, down comes the pantograph by itself.

Not very helpful when, say, trying to pull away from the changeover point when you have just switched to AC
--- old post above --- --- new post below ---

Could the same system used on the 700s to auto raise/lower the pan be retrofitted on LO units?

Possibly. But it would cost a few quid I imagine.

 

[Domh245]

If thepantograph was taken off at the Westway Bridge, how did it end up getting to Olympia before being stopped for "repairs"? Was it a case of driver knowing about it shortly after and then agreeing to go to Olympia to meet fitters quicker, or would they have only found out after a train going the other way (or perhaps following it) informed the signaller.

 

[tim_lathe]

Not in the slightest, you just engineer this small issue out. All's required is for the "3rd rail present then drop" feature to be overridden by the driver pressing the "PAN UP" button, but that button is two buttons, sufficiently apart on the desk to require both hands, and for them to be live, master switch to be in neutral, therefore due to the SSF on the DSD, the train has to be stopped, or very nearly stopped. If no wire, pan goes up, goes too high and falls again, but he train isn't moving anywhere fast. This is entirely right side,. Forgetting to press the down button before the wire runs out (with no auto feature) is wrong side - you get an out of gauge train for a non OLE line, and in all locations where the wires about to disappear you have a 3rd rail, so it is fail safe. Obviously, in case of HT trips or the VCB not closing after a neutral gap, you'd need a separate "AC SYSTEM RESET" button. All these things are possible, but, they do cost - I grant you.

 

[redbutton]

377/7 units have pneumatic shoes that have to be lowered onto the conductor rail in order to switch to DC, so the if-DC-then-drop-pan idea wouldn't work.

I've never been in a 378 cab so I don't know if it's the same on those units, however.

 

[tim_lathe]

The presence of a live 3rd rail does not necessarily require a shoe contact. There are many hall effect (sense the H field or flowing current) or alternatively E field sensors on the market. Such things could sense the live rail and do the job.

Another idea, and one that has intrigued me for some time is a development of the Neutral Gap track inductor system, which currently drops the VCB over a gap and then closes it again. The idea is that neutral gaps are several tens of metres long, representing several seconds between the inductors, even at speed. What if you had two or three in much quicker succession? This would indicate to the train that there is a forthcoming end to the OLE and drop the pan. Obviously the time period between the two or three inductors is dependent on speed, but then all modern rolling stock has an on-board computer that knows that and therefore could work out the distance. This system requires nothing except software, the required hardware being fitted already. The obvious engineering risk with this idea is that the train fails to sense the inductors, but you reduce that by having inductors and sensors on each side of the train, which I believe are already there. Also, the driver can check that the conversion has occurred. Train drivers are very skilled men and most of the time get it right, my ideas deal with the odd occasion that humanity does humanity and a mistake is made. Is this ALARP - who knows, but it's more down that road than the driver having to remember with no backup every time.

Once again raising the pan and converting to AC would require positive driver input.

In fact the communication between train and track by successive magnetic pulses is a very interesting idea, to me anyway.

A much simpler idea is remove the 3rd rail 200 yds before the station where a switchover is needed, the train coasts in (obviously batteries to sustain lighting etc). The train is modified to know that when the shoes are down, but there's no volts, to raise the shoes and prime the pan up for driver command. The other way, sense the 3rd rail with an E field device, drop the shoes and drop the pan.

All these things are possible with modern technology, but the certification requirements are the (expensive) issue.

 

[philthetube]

377/7 units have pneumatic shoes that have to be lowered onto the conductor rail in order to switch to DC, so the if-DC-then-drop-pan idea wouldn't work.

I've never been in a 378 cab so I don't know if it's the same on those units, however.

S stock will not take power from 2 sources, if it picks up from depot shed leads and shoes there is an automatic brake application, I would have thought something similar would be easy to engineer, couple that with pneumatic shoes which can be lifted as the pan is lowered and you should have a fail safe system

 

[ComUtoR]

Does a 378 have a dual voltage alarm ?

 

[Deepgreen]

So - does my idea of a physical inverted ramp fixed to the underside of bridges to 'catch' and guide downwards raised pantographs under the bridge (rather than the bridge simply hitting and destroying it) have any merit? I would have thought it would be a cheap and fool-proof (through being a fixed physical rather than systems item) means of saving at least significant damage, to the extent that trains could still continue in service after an encounter.