Episode 2 – Potters Bar

Potters Bar Script

Podcast Introduction

Intro sting

Hello and welcome back to Signals to Danger.
This is our second episode and I’m really happy to invite you all back for round two. I just want to start out by thanking everybody who listened to episode one. I didn’t know how much interest there was going to be in this subject matter and I’ve never done a podcast before, but it was really exciting to keep getting emails from my hosting service telling me how many downloads the first episode had received. 
Because I know that at least a few people have listened to that first episode, I’ve done some extra bits and bobs between then and now. Knowing that people are out there I’m going to try and really improve the production quality. 
First and foremost, we’re now available at more and more locations. You can stream us from Spotify, Apple Podcasts, Google Podcasts, Stitcher, and Tune-In, so we’re almost at the point where I can say “find us wherever you get your podcasts from”. The other exciting thing is that we now have a website. If you go to www.SignalstoDanger.com, you’ll find our shiny new website. Not only can you also stream the podcast from there, you’ll find an episode guide which includes some additional information on the accident in question, a couple of images to help underline the points discussed and links to the sources I used. 
With all of that in mind, I would also like to interact with you fine people listening to some extent as well. On signalstodanger.com there’s a contact form if you want to leave a message, or we now have a social media presence on Facebook and twitter, so feel free to make contact through them as well. Search Signals to Danger on Facebook or @signalstodanger on twitter.
Now I know that railway safety is fairly prominent in both mainstream and industry media right now due to the ongoing investigation into the derailment at Stonehaven. I am planning on covering this but not until the RAIB and Police Scotland investigations are complete. Speculation has been prominent in recent weeks and I don’t wish to be part of that.
The very last thing I’ll say before we get started is to share a little bit of feedback I received from last week’s episode. After I published it, and plugged it a little bit on my own social media, I was contacted by a former colleague on LinkedIn who shared his experiences of Great Heck from back in 2001.
Robin had been GNER’s head of planning and performance at the time of the accident, and due to catch the incident train down to a meeting in London. His plans changed on the morning and he ended up walking across to their headquarters. As he arrived in the office, he started to hear people talking about a derailed train. In a world before social media, drip fed information arrives much slower. A train colliding with a car on a level crossing gradually became something clearer and terrible.
Robin actually ended up attending site to help co-ordinate GNER’s response and told me how he had found the scene as they drove up to the wreckage. Even 20 years later it’s obvious that these scenes remain clear in his mind and this certainly doesn’t surprise me at all.
Moving on from our last episode then. 
Sadly, Great Heck is not the only disaster to have occurred on Britain’s railways, so without further ado, it’s to for us to start on this weeks episode;

Episode Prelude

There are several images that have been burned into the public psyche after disasters, images splashed over the cover of newspapers and television screens for days and weeks. Images which show the forces involved and the destruction left behind. Images such as the nose of an airliner on a Scottish hillside after Lockerbie and the Herald of Free Enterprise laid on its side in the shallows at Zeebrugge. 
In 2002, the image in peoples minds was the final carriage of a passenger train wedged sideways under a station canopy, swarmed by the emergency services.
This episode, we’re headed to Potters Bar.

Opening Credits

This is Signals to Danger, A podcast where we look at major rail disasters which have occurred in the UK, explain what happened, how the investigation was carried out, and how each of these accidents shaped the industry going forwards. 
I’m Dan, I’m work within the rail industry in my day to day life but today I’ll be the one taking you through this podcast.
This time we’re in 2002. The year after Great Heck, which we covered last time.
Again to put some context on the year, on january 1st, the Euro was officially introduced, bringing much of Europe under one currency. The winter olympics had been held in Salt Lake City during February and Queen Elizabeth the second marked her 50th year on the throne. 
All of this had occurred before we reached the 10th of May.

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One Tango Six Zero. On the 10th this was the 1245 West Anglia Great Northern service from London Kings Cross to Kings Lynn, the traction on this was a class 365 electric multiple unit, 4 carriages long and operated by Driver Gordon Gibson. 
There was no guard on the train, as West Anglian Great Northern (or Wagn, as they were often referred to) ran this as a Driver Only Service. 
Carved out from British Rails Network Southeast, WAGN was the franchise which covered services from the capital up to the Norfolk coast, and the first part of this journey takes us back to the same route we were on last week, just a lot further south. The East coast main line.
As we said last time the ECML is one of the two main routes from London up to Scotland, due to the length of that journey, as much of that route as possible is set up for high line speeds. Although the maximum is 125 miles an hour, it’s not unusual to find line speeds of 90, 100, 115 throughout the route, even through stations.
That was the case at Potters Bar Station. If you want to picture the layout of the station, it has 4 platforms arranged over two islands, with a station building off to the side. Both islands and the station building are connected by a subway. platforms 1 and 4 are the slow lines and 2 and 3 in the middle are the fast lines. the northbound lines through 1 and 2 were the down direction, leaving london. 
The line speed through the fast lines is 115 miles an hour and as 1T60 approached Potters Bar it was travelling at around its maximum permissable speed of 100. 
At approximately 1255, as the front of the train entered the station, Driver Gibson felt a slight jolt, as if the train had lost power, so he eased off slightly on the controller. He then felt more jolts which started to feel more severe and he reported hearing a sound which he thought could be a faulty traction motor.
He started to apply the brakes of the train at this point, but then the jolts and bangs became far more severe. Suddenly all the lights in the cab went out and the trains brakes automatically applied fully. 
Once his train came to a stand, driver Gibson looked out from his cab window and saw smoke and dust to the rear of his train. Assuming, rightfully, that his train had derailed, he sprung into action and followed his training. He tried to make an emergency call on the cab secure radio, but the call didn’t work. He grabbed his track circuit operating clips (abreviated to TCOCs) and placed a set on the up fast line in the opposite direction. 
To understand why he did this, we first need to understand track circuits. In brief, track circuits allow the signalling systems to tell whether or not a train is in a certain location. They also control automatic signals on the network. Power is run through both rails, and when a train is in that section the axles short out the circuit and this tells the systems that that block is occupied.
The TCOCs are 2 metal clips connected by a metal cable. They work by tricking the signalling system into thinking that a train is in the section, replacing the axle of the train with the cable. As Gordon Gibson placed them down on the Up Fast, this would have tricked the signalling system into thinking there was  train there, automatically placing any protecting signallers to danger.

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In Kings Cross Power signal box the clock ticked to 1255. one of the signallers was quietly observing his are when he was suddenly confronted with a host of alarms. 
These were identifiable as being two sets of points showing out of cerrespondance and a number of track circuits showing unexpectably occupied in the area of potters bar.
Following on from what I’ve just explained, the track circuit alarms meant that the system believe there was a train where they shouldn’t have. Points out of correspondance means that the detected position of points (junctions between tracks) doesn’t match the poisition they’ve been set to, the setting doesn’t correspond with the position.
Knowing that this potentially meant something had gone wrong, the signaller immediately placed two signals to danger in the down direction to protect the area, and then his colleague did the same in the UP. No trains would now be moving in the are of the station.
After this he started to contact trains he knew were in the area. He managed to get hold of a southbound train, which he confirmed had stopped at a red signal before the station, he then tried to contact Tango 60, but didn’t get a response. Afterwards he tried to speak to the driver of another train which should have been sat in platform 4 at Potters Bar, but again, he recieved no answer.
And then he recieved a phone call of his own. From an office on a platform at the station. Paul McCarty, a Production Supervisor confirmed the worst fears of the team at Kings Cross. He confirmed that a major incident had taken place and asked to be connected with the Duty Shift Manager.
This call confirmed the DSMs worries, he had just been involved in a discussion with the Electical Control Operator about some the loss of electical power to the overhead lines between Alexandra Palace and Potters Bar. 
He contacted the emergency services to arrange a full response, speaking first to the fire service and then the police. 

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The site that faced arriving rescuers was split into two definitive areas. 1 Tango 60 could be found 289 metres north of Potters Bar station, The two leading vehicles were undamaged, however that is where this condition came to an end. The third vehicle didn’t get off so lightly. The pantograph, which takes power from the overhead lines, was damaged, there was damage visible to the trailing bogie and the solebar, the beam running along the length of the train onto which the bodywork sits. the trailing bogie of the third carriage was derailed. 
The fourth vehicle was not there. This brings us to our second part of the rescue site. At the south end of Potters Bar station, was the last carriage of the Kings Lynn train. it was horizontal between the two platforms, almost creating a footbridge between them. Tilting about 45 degrees to the south it was wedged between the platform Canopy and the platform surface. It was clear this was where the more serious injuries would be found.
It’s trailing bogie had been ripped clear and there was visible damage to the bodyshell.
Small balance weights and a block of concrete had made their way into the carriage, a piece of steel was stuck through the solebar and all but three of the windows had shattered. 
Inside the carriage damage was found to a large number of the seats on the left hand side. 

One of the reasons Potters Bar features so heavily in peoples minds when they think train crash, is because of the location. The train wasn’t in a cutting or in a remote location. It was wedged their on platforms directly next to a supermarket car park, in the middle of a town and raised up above it for everyone to see. 
There are no shortages of photographs and video footage of that sight which made it into print and television media in next to no time.

Evacuation was a mixed bag of challenges, people who had been on the station, or on the stopped train in platform 4 at the time of the accident were quickly escorted by staff to a position of safety off the station.
The leading three carriages of tango 6 0 were a more complex matter, a revenue inspector on the lead portion was able to reassure the passengers and noted that one had been injured. Once the inspector had spoken to BTP and arranged for the injured party to be rescued he waited with them until next steps could have been arranged.
Eventually the passengers were helped down ladders to the ballast and escorted along the track to the adjacent supermarket car park.

At the fouth carriage, wedged in across the platforms, the rescue effort started immediately. Members of the public and station staff started first aid immediately, trying what they could to assist the injured. As the efforts started to ramp up, they were joined by trained first aiders from the adjacent offices bringing additional first aid kits. 
As soon as the emergency services arrived on the scene they took charge of the rescue efforts from the rear carriage, and used ladders, tools and other peices of firefighting and rescue equipment to do what they could.

The thing that might not be obvious to the railway men and women rapidly becoming involved in this accident, is that a third accident scene existed. Directly south of Potters bar station there is an underbridge. This bridge allows the traffic on Darke’s lane to pass under the tracks. Either side of the roadway are footpaths that are raised up to 6 feet from the road surface. 
Underneath this bridge Darkes Lane had been blocked by fallen debris and vehicles. This debris wasn’t just on the carriageway itself, but also over the footpath next to it.

When the rescue operations across these three sites was completed, the sad truth became clear. Yet again lives had been lost on the British rail network.
The six people who lost their lives on the train were 75 year old Austen Kark, 
29 year old Emma Knights, 
25 year old Jonael Schickler
42 year old Alexander Ogunwusi
29 year old Chia Hsin 
and 30 year old Chia Chin Wu
Particularly tragically is that they were joined by a seventh victim, 80-year-old pedestrian Agnes Quinlivan, who had been walking along the footpath on Darkes lane at the time, struck by debris as it fell from the bridge.

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With the rescue and recovery completed, it became important to discover what had turned another normal, every day journey into disaster.
Immediately after the derailment, all of the interested parties made arrangments to bring senior technical staff to the scene. WAGN and Railtrack arranged for their teams to arrive, and they were joined by the private contractor Jarvis, a company which provided maintance support services to the network. In fact they were the infrastructure maintainance contractor for that line. 
At 1328 Railtrack informed Her Majesties Rail Inspectorate of the accident and shortly after 1700 they, and BTP took over the invesitgation.
Just as at other accidents, they needed to understand a series of key points to explain the deaths of 7 people, and the injuries sustained by many others.
⦁ Firstly, what mechanism had caused the train to leave the tracks at 100 miles an hour.
⦁ Had any opportunities existed for the railway’s safety systems to  prevent this accident been missed?
⦁ Finally, had the vehicles involved performed adequately in terms of their crashworthiness?

The first point was the most important in the early part of the investigation. With nearly 11 thousand miles of railway in the UK with thousands of services, knowing any potential fatal flaws was incredibly important to safety going forwards. 
Most, but certainly not all derailements, take place where tracks are not straight and level. The unbroken straight rail is pretty good at keeping train and track together. There are the odd situations where this isn’t as simple as this (google hunting oscillation if you fancy reading up on odd quirks of physics), but generally they happen in one of two locations. The first, is where the railway turns corners. This can take the form of a train travelling too fast for the location, such as the, well, multiple derailements on Morpeth curve, or due to failing components caused by the increased stress in these situations leading to accidents like Hatfield. Again, both things we’ll cover on this podcast in the future.
This was ruled out at Potters bar, the lines on the northbound approach to  the station are as good as straight, and they take on a gentle right hand curve afterwards. The lack of curvature is reflected in the linespeed of 115 miles an hour here on the fast lines where our train was travelling. 
Curvature wasn’t to blame.
The second place we often find derailements are where tracks split or join, junctions known as points. these are locations where pieces of metal physically move and direct the wheels from one set of tracks to another.
This was a much more likely possibility when we start to look at the track layout around potters bar. 
The station has 4 platforms, 1 2 3 and 4, immediately south of the station is the Darkes lane underbridge, which actually consisted of three bridge structures, one carrying both fast lines in the middle and one for each slow line at each side of it.
Further south are a number of points to allow trains to move from between the fast and slow lines on approach to the station.

Now, a quick version of points 101. 
For a train to move from one track to another parrallel track actually requires 2 sets of points. The points work in unison and are normally given the same identifying number, with either an A or B appended to differentiaate between them. 
Points are usually referred to as facing or trailing. Facing points are when two routes diverge and one track becomes two, and trailing points where two converge and 2 become one.
The last part of points 101 is this, for trains to be diverted from one route to another requires the rails themselves to move. this is acheived using switch and stock rails. The diverging routes are laid out by the stock rails leaving a gap where they meet. THis gap is filled using the switch rails. These are two parrallel rails which move a few inches in either direction to form either the start of the curve onto the diverging route, or the straight rails on ahead. these rails must stay the correct distance apart and move in unison to maintain the gauge and keep trains on the track. The two switch rails are held in that gauge using peices of metal called stretcher bars. When points are in the most used direction, straight ahead on a crossover for example, they’re said to be in the Normal Position. If they’re if the other position, they’re referred to as being in reverse.

With all of that in mind, it’s clear to see how the investigation started to focus on 2182A points.
2182A was the facing points located on the Down Fast line. These were facing points that when used in conjunction with 2182B points formed a crossover that would allow a train on the fast lines approaching potters bar to enter the slow platform. While the speed on the down fast line was 115 miles an hour, the allowed speed over this crossover was only 30 miles an hour.
As the train passed over these points just before the station, it was only natural that they be looked at. The first Rail Incident officer recalled seeing Jarvis staff at the points at around 1425 but was primarily involved at that time with arranging the rescue efforts with the emergency services. at the 1800 meeting of the co-ordinating group a decision was made to preserve evidence at the crossover and plastic sheeting was fitted over the switch rails at 2182A.
What was found by investigators was this. The condition of the points fell below the standard that was required for safe operation of trains on the UK rail network .
During the course of the invesigation the following issues were found.
⦁ 2 pandrol clips, the twisting, almost kidney shaped clips which hold the track to the sleepers, were missing from the right hand stock rail. 
⦁ Loose bolts on the heel blocks close to the toes of the switch rails.
⦁ The motor which moved the switch rails was found to be overdriving towards the reverse direction. this meant that when the points were set towards the slow line, the motor was still trying to move the switch rail once it had contacted the stock rail, putting additional strain on the mechanisms.

While all of the above could be indicative of a degredation in the standard of maintainance, they weren’t, on their own, the smoking gun everybody was looking for. But this was found on 2182A as well.
⦁ The left hand end of the front stretcher bar, one of the pieces of metal designed to keep the two switch rails correctly spaced, was found lying down in the ballast, not attached to the rail. No marks indicated it had been struck or damaged as part of the accident. Nuts and the bushes from the left hand connections to the rail were missing, but similiar fixings were found on the ballast next to the switch.
⦁ The lock stretcher bar, the bar at the very tip of the rails was found to have fractured at it’s righ hand side around the point it had been drilled to accept the bolts for the connection to the rail. It was also found that it had been fitted incorrectly and the ends would have been splayed, putting additional strain on the bar itself. Finally around the area the bar had fractured was found to show three distinct conditions. A corroded area which indicated a crack that had grown over months, a brighter area which was estimated to have grown over a few days and small area where the final faliure had taken place rapidly.
⦁ The rear stretcher bar was found to be missing a main nut, lock but and the outer insulating bush. again, similar items were found on the ballast nearby. the movement this had caused had allowed for a narrowing of the flangeway gap. The gap in the points assembly that allows the wheels of trains to pass through safely.
⦁ Just off to the side of the points was an arrangement of cranks and rods called the supplementary drive. for example; couples the movements at the front and rear stretcher bars through an arrangement of rods and cranks. Movement of the points, for example. from normal to reverse, rotates the front crank anticlockwise via the front connection rod assembly. This in turn moves the channel rodding and rotates the rear crank anticlockwise. The arm of the rear crank moves to the right and the rear connection rod assembly pulls the RH switch rail towards the RH stock rail. If that makes sense, in short, it couples the movements and without it, you can’t guarentee the position of the rear stretcher bar is correct. At 2182A points this assembly was found to damaged. 
⦁ The pivots of both cranks were damaged, the pins which held them to their bases were broken and there were witness marks found on the rodding which showed they rods had been positioned incorrectly at some point and there was shown to be excess movement at the front stretcher bar.

Everything I’ve just said is most probably a gross over simplification of the issues that were found at 2182A points, but the detail covers tens of pages of the RSSB report and the vast majority of the accompanying appendixes. I hope that I’ve given you enough detail to understand their condition but in a way that can be understood.
The evidence found here was enough for investigatiors to establish the course of the derailment and the cause of the fatalities.
The first two vehicles of the train had pased over 2182A points without incident, as did the leading bogie of the third.
At, or near the point that the leading bogie of coach 3 passed the points, the right hand switch rail, independantly of the left, closed against it’s stock rail.
The trailing bogie of vehicle 3 and the leading bogie of vehicle 4 encountered the rails in this configuration. All four wheelsets on these bogies encountered a narrowing guage which squeezed them into derailment. 
At that point the trailing bogie encountered the points and, by a mechanism that could not even be understood by the wealth of knowldge invovled in the investigation, derailed but ended up re-railing on the short peice of track that led to the slow line and 2182B points.
As the first two derailed bogies encountered the end of the points, they were deflected further over and the right hand wheels started to run between the rails, aclong the sleepers. While this was in the process of happening, over a serious of seconds, the rear bogie of the fouth carriage continued on the crossover track. 
Because of this the rear carriage started to rotate round to the side so it was approaching being perpendicular to the rest of the train. Just before it reached the slow lines, it derailed again. It impacted with a mast for the overhead power lines and destroyed it, this impact lifting it slightly into the air.
As the train closed on the station, the fouth carriage impaceted the southern end of the Darkes lane underbridge. This impact tore the trailing Bogie from the train and lifted the carriage over a significant portion of the bridge. As it flew over it impacted two of the parapet screens, one becoming attached to the vehicle and the other being knocked into the road below.
Debris from the bridge and component from the train also fell through to the road at this time, and sadly this is what led to the death of Angus Quinlivan as she walked beneath it.
The carriage contined on and reached the end of the down platforms. It continued to rotate around till it bridged the gap between the two, demolishing a waiting shelter, lighting columns and another overhead structure. As all this was occuring the vehicle was also determined to have rolled around 315 degrees by the time it became wedged under the canopies.
Of the people who lost their lives on the train, 2 had passed away inside the rear carriage, however the damage to windows and the rolling had meant that 4 had actually been ejected from the vehicle. 

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Knowing what had physically caused the accident ticked one box for the investigators. But now they needed to understand if it could have been prevented, and more importantly, whether anyone was actually responsible, had anybody been negligent.
It had been established that the fault lay with a set of points which had failed in the course of their day to day work at the worst time and under the worst conditions. 
The condition under which they were found showed inspectors the reason that they failed. The missing bolts, fractured and incorrectly fitted stretch bars and supplementary drive in a poor condition were sadly, very likely to fail. The fact that there were issues with the cranks and rods of the drive, as well as loosely and incorrectly fitted stretcher bars meant that the entire force needed to move the right hand switch rail had been transmitted through the lock stretcher bar at the very tips of the rails, not shared out evenly between all three bars. 
That, coupled with the overdrive putting additional strain on, led to the eventual faliure of the switchset.
As part of the investigation the entire set of points was cut away from the track, and taken away to the Health and Saefty Laboratory at Buxton.
Experiments were carried out in that controlled environment to see what the condition of each component had been. It was here that the overdrive of the points motor was discovered, as well as several loose or incorre tly fitted components. Several of the nuts holding the switch rails in unison were shown that they could be moved by hand, and no evidence was found to suggest that the nuts from the ballast weren’t the ones from the adjacent stretcher bars.
In addition tests were carried out on some of the processes used. The investigation panel, for example, had discovered that no documented or taught procedure trained teams to tighten the nuts on an adjustable stretcher bar. However, they were told by the witnesses the method that was generally used.
The lab was able to ascertain through some extensive testing that while it initially would appear as though this was correctly tightening the fixtures, it was actually storing up the compressive force in the elastomer of the bushes ( a metal and elastomer sleeve which served as an interface between thread and hole).
This meant that all the tightness or compressive load introduced could reduce or even dissapear in a matter of days. It also meant that if a nut on one side of the assembly came loose, the other would follow.
Nuts that were tightened correctly would have transfered no, or very little, of this force into the bushes and the problems simply wouldn’t have occurred.

In simple terms the root cause was a lack of appropriate maintaince of the points. While nobody can tell exactly when and how the missing nuts came off the stretcher bars, it’s clear that proper maintaince and training would have prevented them loosening dangerously in the first place.
Again, this is devoid of the pages of technical detail the reports provide, if you’re of that mind I would recommend a browse, I’m just sure you don’t want a 3 hour epsiode on that one issue.

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In any case. Switches, crossing, signals and sensors. They’re all mechanical and have a shelf life. Metal wears and wire tears. It’s a part of the ebb and flow of the railway and there is an expectation of it. 
To counter wear and tear, every part of the railway is inspected regualrly to ensure it remains safe. From trains to everything they run over. That is the opportunity for these types of incidents to be prevented. And whether oppotunities were missed was the next thing the investigation needed to prove.

At least once a week the continuously welded rails on the fast lines at potters bar required a basic visual inspection, normally as part of a patrol. The pointwork required the same frequency with a maximum of 8 days between inspections. 
As the Line maintainance contractor, Jarvis personell would carry out these patrols.
A supervisor was also required to inspect the switches and crossings of a catagory 1 line once a fortnight. There was also a requirement for a cab ride at least every 2 and a half months… in fact there was a whole host of mandated inspections at mandated intervals. Plenty of opportunities to catch any issues with the infrastructure.
In fact, the final 2 inspections prior to the accident on the 10th of may had taken place on the 1st and the 9th. Nothing of any concern was raised with these points from either patrol. The last supervisors inspection in April had nothing to say about the condition of the stretcher bars on 2182A. 
Additionally the area had been surveyed in July 2001 bya train mounted monitoring system, and in March by a further inspection which took into account critical junctions.
Most of these inspections were recorded as not seeing any faults. However, with regards to the front stretcher bar, the train mounted examination had shown one of the nuts to be more prominant than the other.
The rear stretcher bar had had it’s right hand nuts replaced by the patrol on the 1st of may.
Non of the inspections identified the fracture of the Lock stretcher bar.

The final opportunity for the faults to be noticed and rectified occurred the night before the crash.
A member of WAGN staff, travelling home to stevenage from his role at Finsbury park experieced a rough ride as the train he was on, 1C39, ran over the points approaching Potters bar.  
He described the incident as this;
As the train passed over the Up Fast to Down Fast points the train dipped to the left-hand side. It then seemed to jolt downwards. Then as it passed over the Down Fast to Down Slow points it dipped to the left. As it travelled across the bridge over Darkeís Lane the train lifted and leant to the left, passed over the bridge and then leant back to the right as it came off the bridge. 
When he arrived into Stevenage he told the clerk in the ticket office and asked them to report it. When he arrived home he called his own supervisor and asked him to inform Kings Cross Signal Box. The supervisor passed the details to the member of staff and asked him to contact the box directly, which he did. He was informed maintainence staff would visit the site.
There were a number of phone calls following the report by the Stevenage member of staff which identified the area and the issue reported, however, in a number of the calls the crossover was identified as having been the Up Fast to Down Fast crossover, and not the Down fast to Down slow. This was eventually passed on to a member of railtrack staff and the points identified as 2181, not 2182.
When the WAGN member of staff called the box himself slightly later he gave the headcode of the train he was on, which should have identifed it as a Down train.
The last person to examine the points south of potters bar that night had been the member of staff from railtrack. He examined the points be torchlight and watched them as the next southbound train passed over them. He saw nothing wrong with them, but they weren’t the points 1C39 had crossed over.
The last opportunity to prevent disaster had been missed.

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The last real question of the investigation was on the question of the crashworthiness of the vehicles.
Four of the fatalities at Potters bar were as a result of people being ejected from the fourth carriage as it rolled into the station. 2 other people were also ejected but survived. These individuals were believed to have exited the vehicle by the windows, all but three of which had been broken in the crash. 
The fact is that windows on trains are supposed to remain intact in so far as is possible. This isn’t always managable considering the forces involved in a crash. 
The issue at potters bar was partially due to items entering the saloon and not leaving it. When the carriage had destroyed the overhead line stanchion on the down platform ramp several of the balance weights had entered into the cabin area. The fact that these weighed 40 kg each means that the energy absorbtion needed to resist their entry at 100 miles an hour was orders of magnitude above that which could be expected by glass even if laminated.
I think it’s fair to say that the vehicles involved performed as well as can be expected when faced with this situation.

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The outcomes of Potters Bar were quite wide reaching. 
At the time of Potters Bar Railtrack was the private company responsible for the networks infrastructure, however it was already well on its way to no longer holding that mantle. In fact, Network Rail would come into existance later in the year.
In any case, Railtrack contracted out a great deal of its maintaince to private companies, such as Jarvis. This, in practice meant that the people responsible for the infrastrucre didn’t have ful visibility of the quality of the maintainance it was recieveing. 
One of the first decisions of the new Netowrk Rail was to bring all maintainacne in house. This would give them more control and visibility over the safty of the infrastructure.
The intial HSE reports identified the maintainance as the smoking gun, but the investigations and inquiries didnt stop there.
The final report into the accident was published in 2005 but it wasn’t published by the HSE, it was published under the Acronym RSSB.
The Railway Safety and Standards Board.
RSSB was brought into existance in 2003 upon the recommendation of the public Enuiry into the accident at Ladbroke Grove. The organisation lists its princple objective as being to lead and facilitate the rail industry’s work to achieve continuous improvement in the health and safety performance of the railways in Great Britain.
In the time before the enquiry completed, a new regulator was also brought in to the UK rail industry. The ORR, originally the office of Rail Regulation came into fruition in 2004.
The coronors inquest didn’t reach a conclusion until 8 years later, in 2010. By this time so much had changed. Railtrack wasn’t railtrack any more and Jarvis was just about to enter administration. 
On 28 April 2004, Jarvis had sent a letter to the victims’ families, admitting liability for the accident. The company said that it would formally accept “legally justified claims” after making a financial provision of £3,000,000.
Upon conclusion of the inquest a case was brought in front of the magistrates at Watford. While Network rail held overall responsibility for the track both companies had been brought to court alledged breaches of the health and safety at work act 1974. 
While Network Rail was ultimately fined 3 million pounds, the prosecution was dropped against Jarivs as it’s maintaince arm had gone into administration.

Music Sting

Memorials exist to the people who lost thier lives at Potters Bar, as they do for other disasters. 

As in other places, at potters bar station a garden has been created, just between the station enterence building and the footpath underneath the tracks at Darkes Lane. a slight ramp leads into a stone circle, with a framework constructed so that the plants naturally create a peaceful and enclosed space for reflection.

Ultimately Potters Bar, and the changes made around Nework Rail and the industry’s safety management systems  as a result was the beginning of the end for what had been a very dark period for the countries railways.
In 1997, and then from 99 to 2002, a major accident had occurred every single year, it was becoming expected. 
After this point the gaps widen out. 2004 saw 7 deaths at Ufton Nervert when a High Speed Train hit a car stopped on a level crossing. Then in 2007, the last passenger to be killed on a UK train was the sole fatality when an entire passeger train derailed in Cumbria. 
Until the 12th August 2020 when 3 people, 2 of them traincrew, lost their lives at Carmont, near Stonehaven. 
I’ve been reading the most recent issue of Rail Magazine and the editorial byline on Nigel Harris’s comment reads 13 years, five months, 18 days since a passenger died on a train.
I know that I’ve certainly said in the past that we do have a safety culture that we can be proud of, and a record in recent years which reflects that. There have been lessons to learn from each accident, and Carmont will bring it’s own, in time.

13 years, 5 months, 18 days. How many lives have been saved in that time by the deaths at Potters Bar and countless other locations?


Thanks again for listening, I really do appreciate it.
Remember, if you want to keep up to date or get in touch find us on Facebook or look up @signalstodanger on twitter. Episode notes and sources can be found at signalstodanger.com.
I think I’m going to move to a fortnightly episode after this one, given the length of time it takes to research and write the episodes it’s probably worth making sure I have the time to do it right.
Thanks again!
The opening credits of this episode were “Light goes away by doug maxwell”, closing credits were “russian river by Dan Henig” and the incidental music was excerpts from “Mountain by JVNA”.