MA-Horus posted:

thisisfine.jpg

jackhunter64 posted:

Speaking of trains eating things, check out this near miss when the barriers at a level crossing went up too early. The new trains on this line are having trouble activating the track circuit that tells the level crossing where it is, you can see the crossing lights turn yellow to red then back to yellow because it thinks the train's gone past.

https://www.youtube.com/watch?v=zhlk6JxwEkQ

The train went hungry that evening. The humble cars and vans live another day.

OrthoTrot posted:

It seemed well received so I’ll have a look at explaining Clapham Junction now. This one is a biggy so I think I’ll split it up. To really get the gist of what went wrong its worth going into a bit of detail about the basics of how signalling works.

The safety of UK railways is founded almost entirely on track circuit block and distance interval working. The basic principles of that are sound and allow trains to travel at high speeds extremely closely to each other with pretty much no prospect of any accident. At Clapham the basic principles of track circuit block went badly wrong.

When the railway was new safety was governed by time interval working, i.e. only a period of time separated trains. A train went along the track, a period of time was measured, then another train went along the track, and so on. You can see the problem. There was no method of any kind to communicate with the trains. So no one knew what had happened to that first train. It could have reached its destination hours ago and still no one knew. Or everyone involved could have been killed and no one knew. The time was measured, and the next train was sent.

If that sounds like an incredibly dangerous way of working that’s because it was. But don’t worry – you were much more likely to be killed by the basic technical problems on the engines themselves causing massive explosions than by them ever crashing into each other. So that’s nice.

Distance interval working was considerably safer. A measure of distance rather than time was used to separate trains. The train was sent, you waited until confirmation it had reached the next station, then the next train went. This required communication. Eventually it developed into signallers and signal boxes. Each signal box was responsible for one bit of track. They observed the train arrive and told the previous signal box it was there safely, and therefore crucially had vacated the track between the boxes. Then they asked the next signal box for permission to let the train proceed and if they received confirmation the track ahead was clear, they sent the train on its way.

This, incidentally, is why trains have red lights on the rear. Only by observing the red lights did the signaller know the whole train had arrived and that no divided coaches had been left in the section.

So we had distance interval working and absolute block sections – the railway was divided into sections and if a train was still in a section the next train wasn’t allowed to enter. The next step was track circuit block, which we still use for the most part. This involves an electrical current running through the tracks and connected to the signal – a track circuit. If that circuit has power the green light on the associated signal was lit and trains could enter that section of track. If that circuit lost power, i.e. because train wheels on the track shorted it out, the red signal was lit and trains were therefore told they had no permission to enter that section because it was still occupied. That means every train would be automatically protected in the rear by a red light by very straightforward electrical circuits. In theory.

The only thing to then be added was cautionary aspects where necessary. If a signal was red the signal ahead automatically turned to single yellow, which warned the driver to begin braking. If you have four aspect signalling the signal ahead of the single yellow displayed two yellows – prelimary caution. This means drivers no longer have to be able to react and stop in only a sightlines distance, they can reduce their speed miles before needing to stop because they have been warned of the approaching red signal several signals beforehand. This allows trains to run closer together at higher speeds.

That is no doubt not entirely accurate as a historical picture. But it gives the rough direction of how and why things have developed in the way they have.

On Monday 12th December 1988 several drivers on the northbound approach to Clapham Junction say signal WF138 changed as they approached it. This isn’t unusual in itself. If the train ahead is moving forward you would expect track circuits to become clear as the train moves, causing signals to go from red to yellow, etc. However many of them saw it go from green to double yellow, or double to single yellow. None reported it. There were plausible explanations in their minds for every change, for instance the signaller could have routed a train ahead of them somewhere. The rule book at the time was very vague and only said they had to report irregularities that could be a danger to another train. As they all had reasonable stories in their heads for the change the prospect of danger to trains wasn’t obvious.

However eventually Driver McClymont on the train from Basingstoke witnessed signal WF138 turn from single yellow to red in front of them. They were unable to stop and went past it. This was a signal passed at danger, even if it wasn’t his fault, so he had to report it immediately. He stopped the train at the next signal, WF47 – the last signal before Clapham Junction station, to use the Signal Post Telephone and report it to Signaller Cotter at the Clapham Junction signal box. WF138 then changed back to single yellow, despite the presence of the Basingstoke train on the track circuit controlling it.

Driver John Rolls on the service from Poole was driving normally to the signals he saw and approaching Clapham Junction at about 60mph. There was no data recorder on the train but an off duty driver was sitting in the back cab, which also has a live brake gauge and speedometer. The off duty driver saw the brake gauge go into emergency for a few seconds, and estimated the speed was about 35mph when the Poole train hit the Basingstoke train in a rear end collision.

Driver Rolls was killed along with 32 of the passengers sitting in the front three coaches. 69 people were seriously injured, two of whom later died from their injuries. 415 people suffered minor injuries. The first coach was subject to what the later report described as “complete disintegration”, and the following two coaches derailed. To make matters worse a set of empty coaching stock coming from Clapham on the adjacent line then struck the wreckage and also derailed. It’s not clear if this directly killed or injured anyone, but it definitely didn’t help.

Driver Pike on the train following Driver Rolls saw the wreckage ahead a few minutes later and applied the emergency brakes. He estimated he stopped 20 metres from the crash but it was later measured as more like 60. He walked back to signal WF138, which he had passed at proceed, and saw it was still displaying a single yellow, despite the presence now of three trains in total on the track circuit controlling it. He reported this to Signaller Cotter quite forcefully.

The signal box was examined later that day and it was found that the electrical relay for the track circuit for signal WF138 had an extraneous section of wire. This had intermittently connected current to the circuit when it should have been shorted, so it was still able to show proceed aspects despite the track circuit being occupied. Post two on how that wire came to be there.

OrthoTrot posted:

Part 2 on Clapham Junction:

The wiring on the relays had been put in by a signalling technician called Brian Hemingway two weeks before the crash. This was part of the Waterloo Area Resignalling Scheme (WARS), which had been planned and implemented from 1978 onwards. Waterloo is the busiest London rail terminal, as anyone who has watched the opening scenes of The Bourne Ultimatum knows (it’s the place where Paddy Considine gets shot). Clapham Junction is a major station on approach to Waterloo where the lines from Windsor, Wessex, and Sussex all join. It still proudly boasts it has the largest number of passenger interchanges per day in the whole of Europe.

The signalling for this whole area hadn’t been renovated since 1936. By 1978 the situation was bad. By 1988 it was desperate. So WARS was being implemented rapidly. This involved replacing and re-numbering a large number of signals, including WA25 which was to become WF138. This was done by Brian Hemingway on Saturday 27th November 1988. He put in the new wires but did not take out one of the old ones. He just cut it at one end – still attached at the other. He did not put insulating tape around the loose end, he just pushed it out of the way of the circuit.

This was surprisingly not a problem until two weeks later on, Sunday 11th December, when a wiring job was required, again as part of WARS, on the relay next to this one in the relay room. This disturbed the WF138 wire and allowed it to contact the circuit at its un-insulated end again. By chance the person conducting this work was Brian Hemingway again. On the following Monday morning, when the line was reopened, the signal displayed green or red entirely independently of what the track circuit was doing and instead dependent on whether the wire was making contact in the relay. For the early morning the train service was infrequent and even though the aspects were wrong there was sufficient space between trains that no crash was possible. When rush hour started the trains bunched up and it was only a matter of time before a proceed was shown when a train was physically stopped on that circuit. So the accident happened shortly after 8am. For this very reason the trains were also carrying more people. Over 1500 passengers were on Driver Rolls’ train from Poole.

Why did Brian Hemingway do the wiring job this badly? Some of the mistakes were ones it was later found he always made. Some were ones he made only the day and couldn’t account for.

He was asked why he hadn’t removed the old wire. His answer was he never did that. Not only that, no one who did the same job did that either, so far as he knew. He had never been trained to do that. He had never been questioned by an assessor or supervisor for not doing that. The importance of doing so was not clear to signalling technicians across the board. Anyone could have been doing that job on 27th November and made the same mistake, which is why the inquiry did not find him at fault despite that in his evidence he claimed full responsibility.

His training had been on the job. He’d been working for British Rail for years. Whilst new signalling technicians had a training course when they joined the older ones had not been put on it. Following a series of signal irregularities a few years before an instruction had gone out from BR Standards head office that all signalling jobs must include a count of wires left to ensure all the old ones had been removed. No one could demonstrate that Hemingway would ever have seen this. Even senior managers responsible for WARS weren’t aware this was an instruction. They thought it was a consultation paper, and did not distribute it to staff. In fact, as they thought it was a consulation paper they wrote back their disagreement with it and left it at that. No one from Standards followed it up.

Then there is the issue of his supervision. His supervisor on the day was Derek Bumstead, and the testing engineer was Peter Dray. Derek Bumstead turned out to be supervising in name only as he wasn’t present. Signalling and Telecomms (S&T) were short staffed so he was actually at another site working with a gang on the tracks. That was his style of management. He liked to muck in and help. Neither Hemingway or Bumstead had any expectation that Bumstead would check the work in the relay room. Peter Dray was responsible on paper for conducting testing for this area, but as WARS was a special project it wasn’t clear to him he was responsible for that work as well. A number of management reorganisations over the years had left it very unclear who was conducting quality assurance for what. It was inevitable stuff would get missed eventually.

So we come to the peculiar errors, like the lack of insulating tape. Hemingway reported he always used tape and had no idea why he hadn’t in this case. Remember I said he did the work on both Sunday 11th December and Saturday 27th November? Well in fact he had worked every day in between. Not only that, he had worked all but one day in the preceding three months. Out of 91 days he had worked 90 of them. A survey of technicians in his grade demonstrated that nearly a third had in fact worked every day over that period, and another third took one day off on average every two weeks. The pay wasn’t great so there was a large number of people who would do every hour of overtime they could.

This was in fact common across most grades. My uncle was a signaller in the 1980s and he tells stories now of regularly working nightshifts and getting a call towards the end of it asking if he could come back to cover a late shift just a few hours later. So he would go home, take my cousins to school, sleep for 2 or 3 hours, then go back to work in the signal box. One of the driving instructors I learnt with had been a driver for nearly 40 years. In the 1980s he said he would quite commonly not go home for 2-3 days at a time. He would drive trains, then sleep on a sofa in the messroom for a few hours, then drive trains again. There was no point even leaving the depot.

Local management were asked why they were running their staff into the ground like this. The answer was they were running out of time to get WARS done. It had been on the cards since 1978 but the planning for the actual wiring work for this stage of it wasn’t done until 1986. But even this meant the plan for what work would be done on what days was drawn up two years before the work happened. In that time staff levels changed, so to keep up they just offered more and more overtime to those who were left. Senior British Rail managers expressed shock and dismay, as all senior managers do in these circumstances, that those on the rung down could possibly have thought the project completion date was such an immovable deadline. I cannot roll my eyes hard enough at that. The fact of the matter was the railway ran on overtime. The railway ran on fatigue.

What did we learn?

Fatigue. This is the biggy. The inquiry into the disaster churned out recommendation after recommendation concerning crash worthiness, assurance, training, and risk assessment. In the middle of the 250 page report were just two sentences that basically changed the way the railways run. They required managers to monitor and account for all excessive working by staff.

This may not seem like much but the industry grabbed it with both hands. It's hard to think of anything more influential in the last 50 years in its scope. The report was written by Anthony Hidden, and even now the rules regarding working time on the railways are called the Hidden regulations, or even just "Hidden" (as in "that's a breach of Hidden" or "what does Hidden say about that?").

The rules are:

1. No more than 12 hours in a shift.
2. No more than 72 hours in any 7 day period
3. At least 12 hours rest before any safety critical shift.
4. No more than 13 days out of 14.

In actual fact these aren't even rules. In line with the rather mild tone of the recommendation they are at best guidelines. They can be breached if a manager is comfortable documenting and explaining the requirement to do so. Most railway staff don't understand it that way. It's become so embedded in railway culture that these are seen by most as hard and fast rules. Even those needing cash desperately won't bypass these guidelines for the most part.

Signal irregularities. Drivers are required to carry the RT3185 form at all times. In the event of a signal irregularity, which is now more clearly defined, they stop and call the signaller. The signaller and driver fill the form out together on the phone and both submit it to their managers. Certain types of failure are investigated immediately by technicians on the ground. Until they are satisfied train movements are heavily restricted. This is why signal failures are a massive pain in the arse from a delay point of view.

I will try and grab some photos and the report link asap. I appreciate that people find this interesting. I do too. I'm a fun guy at parties.

OrthoTrot posted:

Here's the Hidden report. Warning, it's loving huge:

http://www.railwaysarchive.co.uk/documents/DoT_Hidden001.pdf

Here's the crash. Driver McClymont's Basingstoke train is on the right. The set of empties is on the left. The front coach of Driver Rolls' Poole train is the few bit of scrap metal looking stuff between the two.

https://imgur.com/a/R0gvZPH

Here's the aerial view of the whole thing:

https://imgur.com/a/W2U580Z

Clapham signalbox relay room:

https://imgur.com/a/fDHDyEH

The offending relay itself, including the wire:

https://imgur.com/a/zVzqwL8

axolotl farmer posted:

I set a scrap of paper on fire with the toaster when the pilot light on my stove had gone out and I didn't have any matches or lighters around.

Dewgy posted:

Technically yes, he was killed by a big sphere.

Memento posted:

Not true at all. I just tested it with the sarlacc pit video up the page and could change it from a postage stamp size to covering most of the page, and that's a gifv

kimihia posted:

"seems a truck spilled its payload of wet viscera all over the 5 this afternoon"

https://twitter.com/jordan_harper/status/1235693997617627136

PHIZ KALIFA posted:

I've literally never been able to make a joke

BMan posted:

this is why we need skul-guns

LifeSunDeath posted:

Kith posted:

https://i.imgur.com/VdwtAR3.mp4

Phanatic posted:

When I was 18 I drove across the country and wound up at one point getting gas in New Mexico. This was before card readers on pumps, so I pulled up at the one marked Regular and went in to pay the attendant. “Fill it up on number three.” He said “it’s regular,” I though “that’s an odd thing to say” and went out to find the nozzle didn’t fit my tank. That’s when I learned that “regular” in some places still meant “leaded” instead of “87 octane.”

Sagebrush posted:

I believe Dirk the Average is pointing out that 400kW/h is a measure of the rate of change of power, so perhaps the engine starts out at 0kW and then ramps up to 400kW after one hour, 800kW after two hours, 1200kW after three, and so on. The instantaneous power figure is constantly changing and the total energy production can be calculated through integration.

e: yeah

Evilreaver posted:

Allegedly from a friend in discord, having bought a shelf from Amazon

McGavin posted:

Pandas eat bamboo.

Cartoon Man posted:

https://i.imgur.com/HZpadzJ.gifv

Spinz posted:

Mandolins should be illegal or like a licensed thing

Kith posted:

https://i.imgur.com/B8llS2y.mp4

CRUSTY MINGE posted:

Nah. You're thinking helicopters.

They might be restricted to the wealthy, the military, and morning traffic bozos, but they'd kill everyone given the chance.

Necrosaro posted:

https://www.youtube.com/watch?v=UztjNapGuKs

The molten steel got a little explody in this crucible transporter.