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Old December 6th, 2009, 12:25 AM   #3901
iampuking
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During the Moorgate disaster passengers who were on the platform noticed that the train raced past the station and appeared to accelerate, it would have taken more than a mistake to cause that to happen!
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Old December 6th, 2009, 01:06 AM   #3902
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Quote:
Originally Posted by Tubeman View Post
I've had a close look at this, and casting my mind back to the line topography from my distant days as a Northern Line driver, I think you're right and here's why...

Moorgate is quite wide, so wide enough to accommodate two tracks side by side without encroaching under property, however Prince's Street is very narrow and therefore below this street the tracks would have to be stacked above one another. When you leave Moorgate southbound, you descend quite a steep gradient before the sharp turn to the left where Moorgate becomes Prince's Street. There's no perceptable uphill gradient approaching Moorgate Northbound, so it's clear to me that the Southbound is descending leaving Moorgate in order to run below the Northbound under Prince's Street. At the southern end of Prince's Street the two lines can again diverge and return to the same level, whilst doing so one needs to curve sharper than the other at the top end of Lombard Street before the platforms under King William Street, and it's logical that the sharper curve is reserved for the slower speed track, which is the Northbound because trains are accelerating on the level rather than decelerating up a gradient into the platform.

This difference in curve radii would explain why it was decided it was better for the Northbound and Southbound to switch round through Bank.

Probably.
Thanks both of you for your answers. It's what I'd guessed in a sense, but good to hear it confirmed. Would be interested in the geometry that means it makes more sense to spiral round each other, twice, rather than just stack, then go back to parallel.
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Old December 6th, 2009, 02:21 AM   #3903
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Whoa. Don't the trains have automatic emergency brakes if you pass a red signal?
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Old December 6th, 2009, 03:35 AM   #3904
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Cheers. The 'daydream' theory and the sameness of stations seem to be one of the more commonly accepted causes.
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Old December 6th, 2009, 06:35 AM   #3905
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Quote:
Originally Posted by hugh
Cheers. The 'daydream' theory and the sameness of stations seem to be one of the more commonly accepted causes.
To whom? How severe would a bog standard daydream need to be for a driver to race past a station at full speed on an otherwise all stopping train, fly over the crossover at a much faster speed than normal and then into the overrun tunnel and into a solid wall? A quick wikipedia search would provide some alternative theories.

http://en.wikipedia.org/wiki/Moorgate_tube_crash

Quote:
Newson was shown to have still been holding the dead man's handle, a device that immediately applies the brakes when released. Not only had he not even put his hands up to protect his face from the impact, but some witnesses even claimed that he had actually increased the speed of the train. The state of the motor control gear as found after the accident indicated that power had been applied to the motors up to a point within 2 seconds of the collision.
The autopsy found no evidence of a medical problem such as a stroke or heart attack that could have incapacitated Newson; he did not appear to have taken alcohol, although post mortem testing for this was hampered by the 4½ days it took to retrieve his body from the wreckage. Dr P A B Raffle, the Chief Medical Officer of London Transport, gave evidence to the inquest and the official enquiry that Newson might have been temporarily paralysed by a rare kind of brain seizure (known as "akinesis with mutism" or "transient global amnesia"). In this situation, the brain continues to function and the individual remains aware although they cannot physically move. This would certainly go some way towards explaining why Newson held down the dead man's handle right up until the point of impact and made no attempt to shield his face. This explanation also supports witness statements that Newson was sitting upright in his seat and looking straight ahead as the train passed through the station.
On the other hand, railway writer Piers Connor, himself a former driver who knew Newson slightly, has suggested[2] that his attention simply wandered from his driving at exactly the wrong moment (this was also the most likely explanation for a similar accident to an empty train at Tooting Broadway in 1971). Arguing against this theory is the fact that the unusually high speed on the crossover track threw many passengers from their seats and some standing passengers fell to the floor: had Newson's mind been elsewhere, presumably this jolt would have brought him around.
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Old December 6th, 2009, 11:37 AM   #3906
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Whoa. Don't the trains have automatic emergency brakes if you pass a red signal?
Of course, but trains don't stop immediately, emergency brake or otherwise. At 30mph it takes a train a train's length to stop, more or less.

All signals have an 'overlap' beyond them taking this into consideration... basically, a signal protecting a train isn't immediately at its rear, it's a braking distance behind. Therefore, even if a train passes the red signal at full speed, it will come to a halt before it reaches the train in front (or junction, etc).

Therefore the incident I described wasn't dangerous, just disconcerting for the H&C driver who was just pulling out of Plaistow bay road to see a District train heading towards them.
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Old December 6th, 2009, 11:59 AM   #3907
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Originally Posted by iampuking View Post
During the Moorgate disaster passengers who were on the platform noticed that the train raced past the station and appeared to accelerate, it would have taken more than a mistake to cause that to happen!
I've accidentally accelerated when I meant to brake before.

D Stocks have a 'deadman' which you push forward to accelerate and pull back to brake, whereas C Stocks you rotate clockwise to accelerate and anticlockwise to brake, because of the configuration of the 'deadman' on C Stocks this equates to pushing forward to brake and pulling back to accelerate, so there's a conflict.

I was coming into Putney Bridge Westbound driving a C Stock, which is a 10mph crawl all along the platform so you 'coast' all the way along (i.e. not drawing power or braking). At the last moment when I went to apply the brake to stop, I pulled back instead pf pushing forward D-Stock style and lurched forward. Again, it was an 'autopilot' issue... I must have momentarily forgotten which stock I was driving. It registered within a couple of seconds and I applied the emergency brake, just about stopping in time.

I don't think it explains Moorgate though, as he was driving a '38 Stock, which had separate brake (left) and motor (right) controls and moreover would have driven nothing but '38 stocks day in day out so I can't see how you could accidentally motor when you meant to brake. I don't know if the theory is he left Old Street in 'full parallel' and never shut off or if he was coasting and then 'wound up' for some reason as he passed through Moorgate platform. If he left Old Street in parallel and never shut off because of some sort of seizure, the train might have got up to perhaps 35-40mph by the time it reached the crossover at Moorgate, and I'm pretty certain at that speed it would have derailed. If however the theory is he was coasting into the platform and then 'wound up' and had a seizure, this is inexplicable as there is no reason why a driver would motor coming into a station, especially if by all accounts he was speeding anyway.

Maybe it was suicide after all?
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Old December 6th, 2009, 07:11 PM   #3908
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http://www.bbc.co.uk/iplayer/episode...s_11_Moorgate/

Last edited by hugh; December 7th, 2009 at 03:50 AM.
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Old December 8th, 2009, 06:00 PM   #3909
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Quote:
Originally Posted by Tubeman View Post
[IMG]http://i47.************/am9lro.jpg[/IMG]
Thank you.

Nice photo.
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Old December 8th, 2009, 08:26 PM   #3910
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Thanks for posting. I can't begin to imagine how awful the recovery effort must have been... It took 5 days to get the driver's body out and temperatures reached 40C down there.

The second carriage sliced right through the first and the third rode up onto the second. I suspect one factor may have been the fact that on the Northern City Line at the time they were running Tube size trains through mainline size tunnels, which might have made matters worse by allowing vertical movement.

Two safety feature arose from the Moorgate Disaster which are still in place today, the first is 'Moorgate Control' which ensures trains come into termini slowly by means of speed-controlled 'Trainstops' which only lower if the train is going slow enough (if not the train is 'tripped' and emergency brakes apply).

The second is 'override zones', these are areas above each coupler with horizontal grooves to prevent a car chassis from riding up over the one in front in the event of a collision. The fact that the second car's chassis rode up over that of the first and sliced through the first car at Moorgate was responsible for many of the deaths.

They're quite apparent on this line-up of D Stocks, which were the first stock built with them:

[IMG]http://i45.************/312d8vt.jpg[/IMG]
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Old December 8th, 2009, 09:20 PM   #3911
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Quote:
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Two safety feature arose from the Moorgate Disaster which are still in place today, the first is 'Moorgate Control' which ensures trains come into termini slowly by means of speed-controlled 'Trainstops' which only lower if the train is going slow enough (if not the train is 'tripped' and emergency brakes apply).
I've been annoyed by this feature, or rather some drivers inability to drive the newer cars into such stations smoothly, here in Stockholm. I don't know if it is this exact feature, but I've only ever felt it at end-stations here (slow entry, or a full stop and then slooow to the right place) and it feels like it might have been introduced here as a result of Moorgate. In conclusion: such news and lessons do spread the feature makes a LOT of sense and some drivers need to learn to drive into such stations better.
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Old December 9th, 2009, 08:42 AM   #3912
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Quote:
Originally Posted by Tubeman View Post
Thanks for posting. I can't begin to imagine how awful the recovery effort must have been... It took 5 days to get the driver's body out and temperatures reached 40C down there.

The second carriage sliced right through the first and the third rode up onto the second. I suspect one factor may have been the fact that on the Northern City Line at the time they were running Tube size trains through mainline size tunnels, which might have made matters worse by allowing vertical movement.

Two safety feature arose from the Moorgate Disaster which are still in place today, the first is 'Moorgate Control' which ensures trains come into termini slowly by means of speed-controlled 'Trainstops' which only lower if the train is going slow enough (if not the train is 'tripped' and emergency brakes apply).

The second is 'override zones', these are areas above each coupler with horizontal grooves to prevent a car chassis from riding up over the one in front in the event of a collision. The fact that the second car's chassis rode up over that of the first and sliced through the first car at Moorgate was responsible for many of the deaths.

They're quite apparent on this line-up of D Stocks, which were the first stock built with them:

[IMG]http://i45.************/312d8vt.jpg[/IMG]
The Moorgate Control was applied nationwide - not just on London Underground.

Given your comments on the mental state of the Moorgate driver, could he have thought he was leaving Old Street and that's why he accelerated. Maybe he blackout leaving Old Street, came to, or partly, as the trains cross over to the other tracks, but not remembering the trip from Old to Moorgate, was confused and thought he was still leaving Old Street.

It's a mystery we'll ever solve - but I strongly believe it was a mental lapse of some kind.
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Old December 10th, 2009, 12:42 AM   #3913
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The Moorgate Control was applied nationwide - not just on London Underground.
I'm not sure about that... Especially considering the trainstop / tripcock system is to my knowledge only used on LU in the UK.

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Originally Posted by lightrail View Post
Given your comments on the mental state of the Moorgate driver, could he have thought he was leaving Old Street and that's why he accelerated. Maybe he blackout leaving Old Street, came to, or partly, as the trains cross over to the other tracks, but not remembering the trip from Old to Moorgate, was confused and thought he was still leaving Old Street.

It's a mystery we'll ever solve - but I strongly believe it was a mental lapse of some kind.
The more I think about it, the more I can only conclude it was suicide. I simply cannot see any combination of events which could have made this an accident.
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Old December 10th, 2009, 04:33 PM   #3914
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Read this: http://www.abandonedstations.org.uk/...e_station.html

It contains some ideas and thoughts of the cause.

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...or rather some drivers inability to drive the newer cars into such stations smoothly, here in Stockholm.
Same here.
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Old December 10th, 2009, 08:19 PM   #3915
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Question

Why do the northern line tunnels flip round between Bank and London Bridge?You leave one station 'driving on the left' and arrive at the next on the other side - weird. (I think it's these two stations - I noticed this a while back and have been meaning to ask for some time)

THanks in advance
A bit more of a definite explanation...

"Reverse running operated on part of the line; between the road junction of Newington Causeway and Borough Road (between Elephant & Castle and Borough stations) and Swan Lane (just north of the river Thames). Thus the short distance between Swan Lane and King William Street station had 'normal' left hand running. No satisfactory explanation has been given for the reverse running.

When the line was extended northwards in 1900, the right hand running continued north of Elephant & Castle until there was sufficient clearance to build a new 'righting' of the tunnels (between Bank and Moorgate stations)"


From here

Here's a good find; Greathead's engineering drawing of the original C&SLR. You can see normal left hand running departing King William Street, then the northbound stacked on top of the southbound under the narrow Swan Lane (to minimise the uphill climb into King William Street for Northbound trains). The lines then diverge, but with reverse right-hand running under the river, remaining right-hand all the way to a point south of Borough station. Because the extension to Moorgate branched off the original King William Street tunnels north of Borough, the right-hand running was continued on the new line. I don't see why it couldn't be reversed back until north of Bank, but I guess with deep-level tube single bore tunnels it really doesn't matter which way around the tunnels are.
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Old December 11th, 2009, 09:24 AM   #3916
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I'm not sure about that... Especially considering the trainstop / tripcock system is to my knowledge only used on LU in the UK.

.
Okay - so not exactly the same, but the crash did cause changes to the way trains are signalled into terminus stations on the then BR network.

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The then national rail company, British Rail, became concerned at the possibility of a similar event happening at a terminus. An early consequence was to change the signalling system so that a colour light signal would not show green on approach to a dead-end terminus. This effectively regarded the fixed stop light at the buffers as part of the signalling system and required an appropriate 'caution' aspect to be displayed at the preceding signal. The displaying of a caution aspect in turn caused the Automatic Warning System horn to be sounded if AWS was fitted. This had to be acknowledged or the train brakes would be automatically applied. The eventual adoption of slow speed control when appoaching dead-end platforms as part of Train Protection & Warning System can be traced back to the Moorgate tube crash.
Source: http://tripatlas.com/Moorgate_control
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Old December 11th, 2009, 05:22 PM   #3917
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Okay - so not exactly the same, but the crash did cause changes to the way trains are signalled into terminus stations on the then BR network.

Source: http://tripatlas.com/Moorgate_control
Oh ok yes I was aware of that; for example the 'home' signals which give you the platform at Wimbledon and Richmond as a District Line driver never show green, only red or yellow... Although you can get a green on the Wimbledon one if you're being signalled across to the mainline (which you're most certainly not supposed to accept as a District Line driver, because you'd run out of 4th rail and grind to a halt!).

It's nowhere near as robust as the LU method though; any platform without an over-run beyond will have 2 or 3 speed-controlled trainstops which only lower at increasingly slow speeds; usually the first about 1/4 way down the platform is 15mph, the second halfway down is 10mph, and the final one 3/4 way down is 5mph. There's then a 'fixed' trainstop just beyond the stopping mark, followed by a pair of fixed red lights, followed by a sand drag.

Even if you were suicidal and intent on re-creating Moorgate, you couldn't, because if you cut out the tripcock to prevent the trainstops from 'tripping' the train for going too fast the speed on the train is limited to 7mph, so very worst case you could engineer a 7mph crash, and even then the sand-drag might be enough to prevent running into a solid wall beyond and would take much of the sting out if not.

Effectively all the NwR method does is give the driver a visual / audible warning they're passing a caution signal, there's nothing physically preventing them from slamming into the buffers at full pelt. Evidence is the 1991 Cannon Street crash where a train rammed into the buffers at Cannon Street, killing 2 and injuring 500. This was only at 10mph, and not helped by the low structural integrity of the aged slam-door EMUs and the fact that the busy train would have been full of standing passengers just about to disembark.

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Old December 12th, 2009, 02:54 AM   #3918
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One interesting point which springs to mind; at Gunnersbury 'up' (= Eastbound), the station starter always shows a caution (yellow) aspect when it gives the District Line route towards Turnham Green, because there is no link between the Network rail signal box and Earl's Court LU signalling centre so the starter signal has to warn that the next signal will be red (even though it never is).

It's an instant indicator to a District driver that you've been given the wrong signal at Gunnersbury, when you see a green aspect... Because that means you've been signalled toward South Acton. Fortunately there is a train's length of fourth rail heading towards South Acton just in case you accept the wrong signal.

I once had to do that move in anger; there was a major defect on the westbound track near Kew (an engineer had accidentally left a tool by the positive current rail, and it drew an arc which turned into a blowtorch, melting through the rail), so only the eastbound road was operable. I happened to be the train marooned on the Richmond branch, so I shuttled up and down the eastbound road single line working, and when the defect was finally fixed I shunted back from the eastbound road between Gunnersbury and South Acton to the westbound at Gunnersbury. It felt very weird accepting the signal at Gunnersbury to go towards South Acton!
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Old December 18th, 2009, 10:36 PM   #3919
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might switching from spacious trains to cramped ones signify demotion over there?
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Old December 19th, 2009, 11:29 AM   #3920
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The D-stock is a sub-surface stock, so is quite generous in terms of space, plus the Overground only runs 3 tph on that stretch anyway.
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