北京地铁事故背后的技术原因，萌萌战队科普频道告诉你

最近，北京地铁发生了一起事故，引起了社会的广泛关注。网上流传的视频显示，车厢被撞裂，有人员受伤。官方的解释也含糊其词，试图淡化事故的严重性。到底事故是怎么发生的，有没有更深层的原因？一个知名的科普频道，从专业和技术的角度，对事故进行了分析，还原了事故的真相。

据官方公布，事故的原因是前车因故障停在了铁轨上，导致信号降级，后车因制动不及，发生了碰撞。这起事故造成了100多人骨折，所幸没有人员死亡。这个说法让一些博主不买账，他们认为国内的重大事故发生的频率越来越高，与经济下行、政府财政收入减少、公共安全投入不足有关，甚至把这起事故和天津的爆炸联系在一起。

这个说法虽然有一定的道理，但是就事论事的话，这起地铁事故还算不上什么严重的事故。网上有一个著名的萌萌战队的科普频道，每当有一些热点新闻，他们都能从非常专业和技术的角度进行分析，非常有意思。关于这起北京地铁的事故，他们也做了一期节目，他们只是从公开的，含糊的官方信息，大致还原出了事故的原因，感觉还是非常有道理的。

按照他们还原的事故经过，涉及事故的车辆实际上是三辆，除了发生碰撞的两辆之外，还有一辆，它才是导致事故最开始的原因。这辆地铁列车停在站台上。地铁一般都是电力驱动的，电力一般是由第三轨输入的。也就是在地铁站台上可以看到的，非常醒目的黄色覆盖的那一根铁轨。停在站台上的这一列，因为不知什么原因发生了第三轨断电的情况，停在站台上，开不出去了。于是它的后一辆列车也只能停在两站之间，等待。

而发生事故的这辆地铁并不是北京市内的地下铁，而是北京和昌平之间的。这一段路线其实是在露天的。我们武汉的地铁去去天河机场也有很长一段是在露天的。所以，因为长距离来说，露天的成本显然比打通隧道要便宜太多了。现在新修的地铁一般都有电脑化的自动控制系统，也就是说可以完全自动运行，不需要人类驾驶，而且也全部由电脑调度。当然这其、中涉及到非常复杂的信号控制。

而第三辆列车，驾驶员不知是什么原因，改用了手动驾驶。但是他仍然收到了前方有停车的信号，他也有采取制动措施。不过此时因为正好遇到大雪天气，铁轨非常的湿滑，所以制动不及时，而与前车发生了追尾。前车被碰撞，向前冲出的时候，有一节车厢从中间被拉断了。这也是后来网上流传出的视频。似乎显得事故很严重，车厢都断裂成了两节。

不过凭心而论，这起事故其实与缺乏维护、政府投入不足关系并不大，顶多也算是类似蝴蝶效应，多种危险因素都赶巧凑到了一起，比如失去供电、天气差、铁轨湿滑。

西方发达国家的轨道交通大都经年日久，并没有采用自动控制系统。中国作为后发国家，在这方面有一定的技术优势，但是新技术也必然没有经过时间足够的检验，是否足以应对极端环境，人类的工程师设计的再周密也不可能做到万无一失，所以人类还是应该对自然有敬畏之心，凡事安全第一，小心为上。

其次，从事故的表现来看，虽然有100多人骨折，但是没有人员伤亡，车厢断裂也很可能是设计有意为之的，因为这样就可以吸收掉大部分的撞击能量，减少对旅客的伤害。总之，快要过年过节了，但愿大家都生活平安吧。

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Recently, an accident occurred in the Beijing subway, which caused widespread concern in the society. Videos circulating online show that the carriage was smashed and people were injured. The official explanation was also vague, trying to downplay the seriousness of the accident. How did the accident happen, and is there a deeper cause? A well-known popular science channel, from a professional and technical point of view, analyzed the accident and restored the truth of the accident.

According to the official announcement, the cause of the accident was that the front car stopped on the track due to a malfunction, which caused the signal to be degraded, and the rear car collided due to the failure to brake. The accident caused more than 100 fractures, but fortunately there were no fatalities. Some bloggers dismiss this statement, arguing that the increasing frequency of major accidents in China is related to the economic downturn, declining government revenues, and insufficient investment in public safety, and even linked the accident to the Tianjin explosion.

Although there is some truth in this statement, this subway accident is not a serious accident in terms of facts. There is a well-known popular science channel of the Meng Meng team on the Internet, whenever there is some hot news, they can analyze it from a very professional and technical point of view, which is very interesting. Regarding the accident in the Beijing subway, they also did a program, and they only roughly restored the cause of the accident from the public, vague official information, which feels very reasonable.

According to the accident they reconstructed, there were actually three vehicles involved in the accident, in addition to the two that collided, there was also one, which was the cause of the accident in the first place. This subway train is parked on the platform. The subway is generally electrically driven, and the electricity is generally fed by the third rail. That is, the one that can be seen on the subway platform, which is very striking and covered in yellow. The train that stopped on the platform, for some unknown reason, had a power outage on the third track, and it stopped on the platform and could not be driven. As a result, its next train could only stop between two stations and wait.

The subway where the accident occurred was not a subway in Beijing, but between Beijing and Changping. This section of the route is actually in the open air. Our Wuhan subway to Tianhe Airport also has a long section in the open air. Therefore, because of the long distance, the cost of the open air is obviously much cheaper than the opening of the tunnel. Nowadays, newly built subways generally have computerized automatic control systems, which means that they can operate completely automatically, without the need for human driving, and are all dispatched by computers. Of course, this involves very complex signal control.

And on the third train, the driver changed to manual driving for unknown reasons. But he still received a stop signal ahead of him, and he also took the brakes. However, at this time, because of the heavy snow, the rails were very slippery, so the braking was not timely, and there was a rear-end collision with the car in front. The car in front was collided, and when it rushed forward, one of the carriages was pulled off from the middle. This is also a video that later circulated on the Internet. It seems that the accident was serious, and the carriages were broken into two cars.

However, in mind, this accident has little to do with the lack of maintenance and insufficient government investment, and at most it can be regarded as a butterfly effect, with a variety of risk factors coming together by chance, such as loss of power, bad weather, and slippery rails.

Most of the rail transit in western developed countries has been used for a long time and has not adopted automatic control systems. As a late-developing country, China has certain technological advantages in this regard, but the new technology must not have passed the test of enough time, whether it is enough to cope with extreme environments, no matter how careful the design of human engineers can not be foolproof, so human beings should still have a sense of reverence for nature, safety first, and caution first.

Secondly, judging from the performance of the accident, although more than 100 people were fractured, there were no casualties, and the carriage fracture is also likely to be intentional by design, because in this way, most of the impact energy can be absorbed and the injury to passengers can be reduced. In short, the Chinese New Year is coming soon, so I hope everyone has a safe life.