 A train collision is to no one's surprise a bad thing. Sadly they are a very common event, on the most part they are relatively minor such as low speed buffer stop bumps, a train hitting something fouling the line or even hitting debris like a shopping trolley. Obviously these events are annoying for those involved as it can cause delays and the like, but usually they don't cause any serious injuries or death. However every so often a larger collision or crash happens which sadly does take life. These types of disasters are the ones they get reported on in the news. Well imagine a train collision within a tunnel. Now everything is multiple times worse. Now imagine one in a tube train tunnel. Now you only have access to the crash site through the affected trains. I mean you can't just get access to the sides like you could out in the open or a wider tunnel. This would be the case of today's story. The 1953 Stratford Tube Train Disaster. My name is John and welcome to Plainly Difficult. Forward. Okay so if I had to pick the underground line that I used the least it would hands down be the central. Us South Londoners would turn to Ash if we went too far northeast. It's a shame as I find the current version of the central line pretty interesting with its automatic train operation based on fixed block signalling principles, the fact that it uses kilometers per hour instead of miles per hour and that it also goes really far into the countryside. Anywho, back when our story takes place the line was very much a conventional London underground line in its signalling and rocks and procedures. So much so that this disaster has a long legacy in the way that trains are operated on the network. It would be the initiating event to change even the way trains safety systems are designed. Now today's video will have lots of signalling chats so this is a geekiness alert. I'm also going to be using the original report into the disaster as the framework for the facts and figures and as always the linky will be in the description. Signals, Trips and Stops. So today I'll be talking about London Underground's conventional signalling system and not so much with its newer TBTC, CBTC, DTGR and ATP ATC systems. The other ones that allow for automatic train operation. So signals on the London Underground are pretty simple and different from mainline operations. On the most part they are two aspect signals. That is green and red. Green for proceed and red for stop or danger. Each safe stopping distance is individually calculated per signal for a train travelling at line speed. That is if a train passes a red signal without authority then the safety system would grind the train to a halt before hitting a potential train in the front. Now how's a train stopped you might ask? Well that involves trip cocks and train stops but there with me I'll come back to this in a little bit. So being in a tunnel one's visibility can be obstructed. As such additional signals are added to warn the driver of the condition of the next signal. These are called repeaters. They can show green and yellow. Thus green means that the signal is repeated is clear and yellow means that it's at danger or red. Now generally on the underground there are two types of signals automatic and semi-automatic. The former are controlled by the passage of trains using track circuit blocks and change automatically from green to red and back to green again depending on the track circuit's detection of a train. And the latter change to red after the train passes over its track circuit but usually will require the signal to return it back to green. This is done from a number of signal cabins spread throughout their respective lines well at least when the disaster in our video unfolded. So like all machines signals have a non-zero chance of breaking down. As such for any case of power loss, track circuit issue, light bulb being out etc then the signal will revert to a failsafe position i.e at red or danger. Thus there needs to be a provision for this as well a train stuck at a red signal in a tunnel indefinitely would cause a little bit of bother. This is where the old fashioned rule 55 comes into play known as the stop and proceed rule. Now this rule has changed significantly in its wording into the modern day but the theory is the same in that if a driver cannot make communication with a signal then after waiting a certain amount of time in 1953 this would have been at least a minute but the train can proceed past the signal at danger under its own authority. The train must proceed at such a speed to enable him to stop short of any obstruction there may be as noted in the Ministry of Transport report. Now for the train protection system. So trains on the underground even in the 1950s had a very effective way to protect rolling stock in the event of passing a signal at danger and that was the tripcock. This is a metal bar that is mounted to the right hand side of the train on its leading shoeming. This is then connected to a valve on the train's brake pipe which after being tripped is open dumping the air to the system thus creating an emergency brake application. It also cuts the power to the train's motors. So what engages the tripcock? Well that is the track mounted equipment known as a train stop. This raises and lowers using pneumatic power when the signal is at danger or clear the train stop will either be in the up or down position. Usually the train stop would be in the up position for danger and down for clear. The train stop raises three inches above the railhead on the right hand side and is then able to hit the tripcock. The system worked pretty well but in the case of a signal failure the train will still have its emergency brake supplied when passing the signal under the driver's own authority. As mentioned in rule 55 the train must then travel at a caution speed until the line is clear. This is vital as if not then one train could rear end another as you always have to assume that there is a train ahead of you. The rules for passing a signal under your own authority have changed on the modern day tube network where if you can't make communication and you've waited a minimum of two minutes and this can't be done at semi-automatic signals, X signals or station starting signals as well as several others. Now the trains used on the central line in the 1950s look pretty ancient by today's standards. These were the standard stock. Even though other stocks used on the network at the same time such as the 38 stock actually still looks pretty modern at least when compared to the standard stock. So when the standard stock was designed traction control equipment was very bulky and as such it meant that behind the driver there was a whole control gear compartment. This also meant that passengers were actually quite a distance from the front and rear of a unit. The formations used on the central line at the time were eight cars and some of the carriages dated back to the early 1920s. They were not too far off replacement in 1953 with a 1959 stock predicted to arrive in the early 1960s. Regardless they were stock on the central line and they had Westinghouse and electro pneumatic brakes, a dead man and that all important tripcock protection. Now it's time for the disaster so get your bingo cards ready. The disaster. So this is strapped for tube station which is around here on a map. In April 1953 the area is under 10 years old and the line has a rising gradient to strapped for station. This is to accommodate cross-platform interchange with British rail services after at Stratford in both directions trains then go back down a gradient to tunnel sections. For today we're looking at three eastbound services from Stratford and Signal Alpha 489. I should say it is the evening of the 8th of April 1953. Two signals are stuck at danger that is Alpha 489 and the next signal Alpha 491. 489 was the starting signal at Stratford and 491 was the next one on the way to Leighton. As part of the protocol porters were posted on the platform to communicate that signal 489 was stuck at danger to the driver and to the guard and also to give them authority to pass a signal at danger. However and very much importantly the porters didn't actually know that 491 was also damaged and stuck at danger. So train 39 pulled into Stratford and was given permission to pass Alpha 489. It did so being tripped in the process and after resetting set off down into the tunnel. It pulled up to Alpha 491, stopped and began to wait for it to clear. Meanwhile the following train number 71 pulled into Stratford was also told by the porters of the signaling issue and to pass the signal and descend down into the tunnel. The driver saw the rear of train 39 and stopped. Now there were two trains in the section of track between Alpha 489 at Stratford and Alpha 491. After some time went past train 39 passed 491 at danger and continued on towards Leighton. Train 71 then began to move forward at a slow speed. Meanwhile the motor man of train 59 was just getting his permission back at Stratford from the porters to pass 489 at danger. He was told the signal was failed you are to pass it at danger. The guard gave the driver the bells and a way they went past 489 tripping the trick cock in the process. Roughly a minute went by as the train pipe recharged with air. Driver Besley took power and the train proceeded down the incline. Bearing in mind the driver wasn't expecting a train ahead although it would be a possibility. Besley saw what he would describe as a cloud of smoke. He would claim he was traveling at a speed of less than 10mph. Almost instantly after hitting the smoke train 59 slammed into the rear of train 71 and this was at 4 minutes to 7 in the evening. The collision crushed the leading cab of train 59. The force of the sudden stop pushed the second carriage up over the first causing it to telescope. The driver of train 71 after feeling the collision contacted the substation operator by the pinch and rub method wires that ran along the tunnel wall. This caused attraction current to be discharged as by design. The guard of train 59 feeling the collision attempted to make his way to check up on the driver however his progress was hindered by the severely damaged carriages. Instead he travelled to the rear of the train and made his way back to Stratford to get assistance from station staff. Driver Besley amazingly was still alive in the leading cab albeit crushed with serious injuries. The West Ham Fire Brigade was on the scene by 7.15pm. Doctors and nurses from Queen Mary's Hospital and Witt's Cross Hospital also attended as well as staff from the St John's Ambulance Brigade and the Metropolitan Police. Many people would be trapped in the trains with two remaining there until 2am. In total 12 passengers had died. 9 were killed outright and 3 died in hospital from her injuries. Many many many more were injured and understandably traumatised from the event. Now the disaster became a logistics nightmare. Two trains were smashed up inside a tunnel, not the best recovery situation, with normal services not resuming until 10am on the 10th of April. Of course the disaster would require an investigation and one would follow from the Ministry of Transport headed up by Colonel D McMullen. The investigation. Investigators pulled over the wreckage and signalling in the area. The failure of the two signals was discovered, a failed train stop at 491, which also caused 489 to fail safe as a kind of form of double blocking, that is having two block sections protected. Damage from the collision led investigators to believe that the impact speed was far greater than 10mph. Contradicting what Driver Besley had claimed. In fact he was driving at a speed to be closer to 20mph. The crash caused a lot more damage to the rolling stock than anticipated. It would lead to a serious consideration for future rolling stocks, where riding up on other carriages would be reduced. Just look at the 95 stock on the northern line with its rubber anti-riding bumpers. Investigators presumed that Driver Besley had lost track of his speed and had coasted down the incline gradually reaching the higher velocity. This was still his fault but a number of factors played into his assumption of no train ahead. The first was that the porters did not inform with 491 being stuck at danger as well. Another was that the porters did not inform Besley that there had only just been a few minutes earlier two trains passed that signal at danger. He was also not reminded to travel at caution, although he probably should have done so anyway. The main issue was that the procedure of passing a signal and proceeding at caution solely relied on the driver and we know that this isn't always the safest option. Even the report into the disaster would state this. This method of working has been found necessary on the executive's tube, underground and surface lines, all of which have a very intensive train service and are equipped with automatic signals remote from and uncontrolled by signal boxes. Generally speaking it is only when stop and proceed working has to be adopted that safety is completely reliant on the human element, otherwise electrical and mechanical devices are provided to counteract its fallibility and to prevent collisions between trains. As a result of the previous accident in Stratford, Lieutenant Colonel E. Woodhouse recommended in his report that the staff should be continually reminded of the risks arising from the non-observance of the caution required by rule 55G. This was met by the annual insertion of a notice in the railway traffic circular and the last reminder appeared in September 1952. These are useful, but it is evident they are not sufficient in themselves and that some more positive action is necessary. And that was long-term channel friend, Zephyrus. Humans are fallible, especially in a restrictive sight environment. Shockingly, it would take until the 1970s before a system would be employed. And this would be the SCAT. And no, there's not what you think. It's speed control after tripping. That is a system that limits the maximum speed a train can travel after being tripped. For example, tripping past a signal. The system limits trains to below 10mph for a time of 3 minutes. Although not perfect, it does work pretty well in enforcing that caution speed after tripping. So bingo card time. This is what I got. And for the scowl I've put it at a 4. Do you agree? This is a plain difficult production. All videos on the channel are creative, commerce, attribution, share, light, licensed. Plain difficult videos are produced by me, John in the currently very windy and cold corner of southern London, UK. I still have this really horrible cold and it sounds like it's getting even worse with my voice. So hopefully next time I record a script, I'll be feeling a little bit better. Anyway, so I have a second YouTube channel and Instagram and ex or Twitter, whatever the hell you want to call it today. And I'd like to have a very warm thank you to my Patreon and YouTube members, as well as the rest of you for tuning in every week to listen to me to all come watch my dodgy cartoons. And all that's left to say is thank you for watching and MrMusic, place out please.