We often hear that “trains are delayed because of a signalling failure”. But why do we hear about it so much, and is it because there are more signalling failures?
我们经常听到"火车因信号故障而延误"。但是，为什么我们听到这么多，这是因为有更多的信号故障？
Signalling is fundamental to the safe operation of the railway, ensuring that trains are spaced safely apart and conflicting movements are avoided. Railway signals are ‘traffic light’ devices, which tell a train driver if it’s safe to proceed along the track. As with road traffic lights, a driver shouldn’t pass a red signal. Signalling failure refers to various things that go wrong, causing a train to be held up at a red signal. A stationary train quickly creates knock-on delays and, with the rail network busier than ever, the knock-on delay can be significant.
信号是铁路安全运行的基础，确保列车安全分开，避免相互冲突。铁路信号是"交通信号灯"的设备，它告诉火车司机是否可以安全地沿着轨道行驶。与道路红绿灯一样，司机不能越过红色信号。信号故障会导致各种出错的事情，导致列车在红色信号处被扣留。停下来的列车会迅速造成联锁延迟效应，如果铁路网更加繁忙，导致列车头晚点可能性就很大。
The total signalling asset count for the GB network is some 500,000 maintainable assets, situated in a wide range of environmental conditions which may affect their reliability and ability to be easily repaired.
信号系统在网络上有约为 500000 个维护设备节点，各种不同的环境条件下，可能会影响其可靠性和易于修复的能力。
Signalling equipment consists of a number of subsystems:
» Control systems - allow a signaller to set routes, using a mechanical locking frame, signal panel or screen-based system;
» Interlockings - ensure conflicting routes cannot be set;
» Points - route trains through a track layout;
» Signals - pass information to the driver - for modern digital systems, such as ETCS (European Train Control System) and the older RETB (radio electronic token block), this is provided via an in-cab display;
» Train detection - provide train positional information;
» Level crossings - allow footpath and road users to safely cross the railway.
信号设备由多个子系统组成：
• 控制系统 - 允许信号员设置进路，使用机械联锁机、信号面板或基于屏幕化人机系统；
• 联锁 - 确保冲突的进路无法设置;·
• 引导 - 列车通过轨道进路;
• 信号 - 将信息传递给驾驶员 - 用于现代数字系统，如 ETCS（欧洲列车控制系统）和旧制式 RETB（无线电电子令牌模块），这可通过驾驶室内显示屏提供;·
• 列车检测 - 提供列车位置信息；
• 平交道口 - 允许人行道和道路使用者安全地穿越铁路。·
Tracks are divided into“sections”of track and normally only one train should be in a particular section at any one time, with signals positioned at the beginning of each section. The signals are controlled via the interlocking which ensures conflicting routes cannot be set by the signaller. An interlocking can be considered to be similar to a locked door into an unsafe building. Only when it’s safe to proceed will the door be unlocked.
轨道被划分为轨道"区段"，通常同一时间只有一列火车在一个特定的区段，信号位于每个区段的头部。信号通过联锁进行控制，确保不会设置冲突的进路信号。联锁可以被视为类似于进入不安全建筑的锁门。只有当建筑安全时，门才会解锁。
However, the interlocking does not check that everything is safe for the passage of a train, it only checks from a signalling perspective. A section of railway track must be safe in other ways. For example, the distance between the rails must be correct and the track-bed must be capable of supporting the weight of the train. Other systems, known as track circuits or axle counters, detect if a train is present in the section.
然而，联锁并不检查列车通过是否一切安全，它只是从信号的角度进行检查。轨道区段必须是其他形式上的安全，例如：轨距离必须正常，道床必须能够支撑列车的重量。其他系统（称为轨道电路或计轴器）可检测在当前本区段的列车。
To switch a train between tracks, signalling point machines move points, but only when allowed by the interlocking. In a modern signalling installation, all these systems require some sort of electrical power supply to function and a large signalling area will require telecoms links to connect the subsystems together.
要在轨道区段间切换列车，信号点也要跟着移动，但仅在联锁允许时才移动。现代信号装置，所有这些系统都需要某种电能信号驱动正常工作，而覆盖较大范围的信号则需要电信设施来连接子系统。
Telecoms GSM-R ( mobile phones for railway control) and RETB base stations are also required to provide a communication path to the train, for movement authorities for ETCS and electronic tokens for RETB. Sometimes, these systems break and the signal turns red, even when there is no train in the section, or, for ETCS and RETB, no movement authority can be sent to the train.
电信GSM-R（用于铁路控制的移动通话）和RETB基站也需要为列车提供通信通路，为ETCS的移动授权和RETB的电子标志提供通信通路。当这些系统会中断，信号变为红色，即使该路段没有列车，或者对于 ETCS 和 RETB，无法将移动授权发送到列车。
Problems with track circuits and axle counters are common causes of signalling failures. A track circuit is a small current running between the tracks and trains, and an axle counter counts the axles and track wheels going in and out of a section - if the numbers match, the section is clear for the next train.
轨道电路和计轴器是信号故障的常见原因。轨道电路利用是轨道和列车之间通过的电流，轴计数器是对进出本区段得车轴数进行计数，如果数字匹配则轨道区段出清可接后车。
Track circuits are susceptible to corrosion and rail contamination resulting in trains ‘disappearing’. This is known as a wrongside failure - a failure where the asset fails to an unsafe condition and one which must be thoroughly investigated so that the root cause is understood and addressed. This can cause further delay until the failure has been independently investigated and signed back into service by a competent person. On the other hand, if flooding was to cause the track circuit to operate and turn the protecting signal to red with no train present, that would be a rightside failure - one in which the system failed to a safe condition.
轨道电路容易受到腐蚀和轨道污染导致列车"丢失"。这称为错误故障 - 设备处在不安全状况导致故障，必须彻底调查以便搞清楚和彻底解决。这可能导致进一步的延迟，直到故障经过独立调查并由主管人员重新生效。另一方面，如果洪水导致轨道电路在没有列车的情况下将保护信号变为红色，那将是一个“正确”故障 - 系统故障并导向安全状态。
Axle counters don’t suffer from rail contamination, poor ballast conditions or flooding conditions that can affect track circuits, but some axle counter systems do not respond well to heat and, in the event of a power supply failure, axle counters will come ‘back on’ and not detect if a train is present in the section. 轴计数器不会受到轨道污染、不良道床或发生洪水的情况的影响，但某些轴计数器系统对热没有良好的响应，在电源发生故障时，计轴不会很好地反应 。计数器将"重新打开"，不会检测轨道区段中是否有列车。
This requires a manual reset, which takes time and further delay. A reliable source of electrical power is vital for modern signalling systems and uninterruptable power supplies (UPS), which take over when the main power supply is cut, are vital. 这需要手动重置，这需要时间和进一步的延迟。可靠的电源对现代信号系统至关重要，不间断电源 （UPS） 在主被电源切换时至关重要。
A lot of investment is being made and, most recently, UPSs have been introduced . They are also provided for all new resignalling schemes. In areas that don’t have a UPS, Network Rail is making the power supplies more reliable by replacing ageing cable. The health of the power supply system and cabling can also be monitored via remote condition monitoring equipment, supplemented by annual inspections. The objective is to fix problems before they become service affecting faults.
大量投资正在实行，UPS 已启用，所有新线信号系统均已作出规定使用。在没有 UPS 的地区，铁路公司正在更换老化的电缆，使电源更加可靠。电源系统和布线的运行状况也可以通过远程状态监测设备进行监测，并辅之以年度检查。目标是要在影响服务故障之前解决问题。
A fail-safe system故障导向安全信号系统
Signalling systems are designed so that, if something stops working, such as a signal or a set of points, trains will stop before they reach that location. So, if there’s a power failure, the signal goes black and the driver knows not to pass a signal unless it has a green or yellow light. If a set of points should fail, the last signal before it will automatically turn red so no trains can pass. On some of the busiest lines on the mainline network, over 100 trains will pass over just one set of points every day, so they must be made as reliable as possible.
信号系统是这样设计的，如果某些原因信号停止工作，则信号或一组信号将在列车将停止之前到达该位置。因此，如果出现电源故障信号会变黑，驾驶员知道除非信号显示绿色或黄色指示灯，否则不会传递信号。如果一组信号发生故障，则之前的最后一个信号将自动变为红色，没有列车可以通过这个点。在 干线网络上一些最繁忙的线路上，每天有 100 多列火车将经过一组点，因此必须尽可能可靠。
Like signals, points can fail. They might get clogged with debris or ice, the drive mechanism might fail or, in hot weather, they might expand too much. Unlike other systems, the point machine is a single point of failure with no back up or duplicate system. When points do fail, the system goes into ‘fail safe’ mode and the protecting signal is made red.
（道岔）信号点也会失效，它们可能会被碎片或冰块堵塞，驱动机构可能会出现故障，或者在炎热的天气下，它们可能会膨胀太多。与其他系统不同，设备是单点故障，没有备份或重复的系统。当点发生故障时，系统进入"故障安全"模式，保护信号为红色。
As points are now monitored remotely, in many cases, problems can be fixed before the points fail totally. Electric heaters and NASA-grade insulation have been provided to stop ice forming and jamming the mechanism, and protective covers have been fitted to 4,000 points and 2,500 point-motors to keep snow out and prevent damage from ice that can fall from passing trains. Improved training for installers and maintainers has also had a positive impact on points reliability.
由于信号点远程监控，在许多情况下，信号在完全失效之前都可以被修复。电加热器和美国国家航空航天局级别的绝缘材料已被使用，以阻止冰的形成和阻塞，已在4000型和2500型转辙电动机上安装了保护罩，以防止雪进入防止冰从经过的火车上掉落造成损害。加强对安装和维护人员培训也对其可靠性产生积极的影响。
Rails are painted white at critical points so they absorb less heat, which reduces expansion. Typically, a rail painted white is 5°C to 10°C cooler than one left unpainted. If points do fail, they can often be secured in one position so trains can pass over. This keeps lines open and trains moving and reducing delay. This will mean staff getting to site, which can be a problem in areas with congested roads or remote locations.
关键道岔信号点的轨道被漆成白色，因此吸收的热量更少，从而减少膨胀。通常漆成白色的轨道比未涂漆的导轨要低 5°C 至 10°C。如果点发生故障，通常固定道岔位置，便火车可以通过。这样可以保持线路畅通，列车移动，减少延误。这将意味着工作人员到达现场，在道路拥堵或偏远地区地区可能是个问题。
Cable theft电缆偷盗
The theft of metal can be a big problem for the railway as thieves target signalling, telecoms and power cables, and even metal fences, to sell for scrap. Cable theft causes signalling failures and costs Network Rail millions of pounds each year. The total, taking into account the impact of freight delays and the cost to passengers who are late for work or have their day ruined, is even higher.
盗窃金属是铁路的一个大问题，因为窃贼会将信号、电信和电力电缆，甚至金属栅栏作为目标，将其作为废品出售。电缆盗窃导致信号故障，每年给铁路网造成数百万英镑的损失。考虑到货运延误的影响，以及上班迟到或一天被毁的乘客所付出的代价，这一数字甚至更高。
A lot of work has gone into tackling cable theft, including funding additional and undercover British Transport Police (BTP) officers, using CCTV to alert when people are on the network, installing new ways of securing cables, using forensic marking agents to make stolen cables easier to identify, and setting up a dedicated security team.
很多工作已经进入解决电缆盗窃,包括额外资金和*底卧**英国交通警察(BTP)官员,利用监控警告当人曝光在网络上,采用新的保护电缆的手段，利用司法鉴定手段，使得被偷的电缆易于识别，并成立专门的安全团队。
Reduction in failures 减少故障
Given the media and social media reports on the subject, it may be assumed that there is an increase in the number of signalling failures occurring on the network. In fact, there has been a steady decrease year-on-year. According to Network Rail, in 2011/12 there were 23,000 signalling failures on the network causing a delay of 100 minutes or more, in 2014/15 the figure was down to just over 20,000 and in 2016/17 it had reduced to 19,000. This is still a lot, as even one failure is one too many, but the trend continues downwards.
鉴于媒体和社交媒体关于这一主题的报道，可以假定网络上发生的信号故障数量有所增加。事实上，同比有稳步下降。根据网络铁路公司的数据，2011/12 年，网络上有 23000 个信号故障导致延迟 100分钟或更长时间，在2014/15年，这个数字下降到刚刚超过20000，而在2016/17年，它减少到19000。虽然仍然是很多，但趋势是继续下降。
The Office of Rail and Road (ORR) is concerned about passenger train service performance in the North West and Central region in England and has, in January 2020, put Network Rail on a warning for its poor overall service, saying that “Network Rail’s performance in terms of its contribution to delays in this region remains a concern”.
铁路及公路局（ORR）对英国西北部及中部地区的客运列车服务表现表示关注，并在2020年1月对网络铁路整体服务差发出警告，称"网络铁路对该地区延误的贡献仍令人关注"。
However, signalling failures in this region continue to improve. The overall number of signalling failures in the North West and Central region was 14 per cent lower, year to date, in January 2020 compared to January 2019. Signal failures were nine per cent lower, level crossing failures 11 per cent lower, signalling power supply failures 24 per cent lower and track circuit failures 24 per cent lower. Telecoms failures contributing to signalling failures were down 25 per cent.
However, permanent way track faults were 14 percent worse and traction power supply failures were 11 per cent worse, hence the ORR concern with the overall poor asset performance. The ORR also looked at the cause of the recent poor performance of Trans Pennine Express (TPE) in the region and found it had been largely the result of train operations and not necessarily asset failures. So how has the reduction in signalling failures been achieved?
该地区的信号故障还有上升。截至2020年1月西北和中部地区的信号故障总数比2019年1月下降了14%。信号故障减少9%，平交道口故障降低11%，信号电源故障降低24%，轨道电路故障下降24%。导致信号故障的通信故障下降了25%。然而，永久性轨道故障和牵引电源故障分别恶化了14%和11%，ORR关注的是整体设备的不良表现。ORR还研究了最近 (TPE)在该地区表现不佳的原因，发现这在很大程度上是列车运营的结果，而不一定是设备失效。那么，信号故障的减少是如何实现的呢?
#Predict and Prevent 预测和预防
redict and prevent’, rather than ‘find and fix’, maintenance is the objective. Key to this is remote condition monitoring (RCM), which is an umbrella term for a number of remote monitoring strategies including points and track condition monitoring using analogue sensors or event monitoring of signalling control logic. These systems are used to monitor and report condition and defects so that action can be taken before failures occur.
我们的目标是“预测和预防”，而不是“发现和修复”。这其中的关键是远程状态监视(RCM)， RCM是许多远程监视策略的统称，包括使用模拟传感器监视信号点和轨道状态或信号控制逻辑的事件监视。这些系统用于监视和报告条件和缺陷，以便在发生故障之前采取行动。
Reliability-centred maintenance, on the other hand, links maintenance with usage and performance. It identifies historic maintenance tasks that cannot be demonstrated to be beneficial to asset performance, so they can be eliminated or, at least, performed less frequently. It also considers possible additional maintenance tasks and frequencies for assets that are used intensively or are of strategic importance. In simple terms, heavily used critical assets are given more attention than lightly used ones.
以可靠性为中心的维护将维护与设备的使用和性能联系起来。它确定不能被证明对提高设备性能有益的历史维护任务，任务可以消除任务，或者减少执行频率。它还考虑可能的额外维护任务，针对频繁使用的设备或具关键性重要性的设备。简而言之，要关注大量使用的关键设备而不是少量使用的设备。
In-built resilience 内置自修复
There is still much to do before “signalling failure” is no longer heard on station PA announcements, news or social media. Even when a potential fault is identified by the maintainer, gaining track access on a busy railway which is operating without a problem can be a challenge, and, when faults do occur, getting the right staff to site can also be a problem in the busier parts of the country.
在PA电台公告、新闻或社交媒体上不再听到"信号故障"之前，仍有许多工作要做。即使维护者发现潜在故障，在运行繁忙铁路上获得轨道通道可能是一个挑战，而且，当故障确实发生时，让合适的工作人员安全到达现场也是一个问题。
This is why new assets have to be designed so that they do not fail, with redundancy and resilience built in from day one. Nowadays, people expect everything they buy, be it a car, phone, washing machine or any consumer device, to work reliably out of the box. When buying new infrastructure, the railway demands and expects no less from the signalling supply industry.
这就是为什么必须设计新信号设备，以便它们不会失败，从第一天开始就内置冗余和自修复。如今，人们期望他们购买的所有东西，无论是汽车、手机、洗衣机或任何消费设备，都可以在开箱就可靠地工作。在购买新的基础设施时，铁路对信号供应行业的需求和期望不再依旧。
New signalling systems are designed with far more resilience than previous ones, with diversity and redundancy built in. Processor-based systems with hot standby and double or triple redundancy are now available and in service, and which are able to have any failed critical components replaced with the systems still operational. The telecoms network now employs‘packet routing’ internet protocol IP, which provides multiple connections for signalling and radio systems.
新的信令系统的设计具有比以前的更具自修复，内置了多样性和冗余性。基于处理器系统具有热备和双重或三重冗余，现已可用并投入使用，并且这些系统能够将任何发生故障的关键组件替换为仍在运行的系统。电信网络现在采用"数据包路由"互联网协议IP，为信号和无线系统提供多个连接。
The reduction in the number of signalling asset failures can therefore be attributed to the large investment in new signalling assets, to targeted interventions and to the benefits stemming from remote condition monitoring that can identify problems before they become failures. Of course, one must also add the sheer hard work and attention to detail of all those involved. A reason for the overall poor performance, and increased media reporting of the problems, is no doubt the greater number of train services on the network along with the large number of passengers on those trains. It only takes one signalling failure to delay a busy train and the internet is immediately full of tweets and other messages informing the world of yet another “signalling failure”!
因此，减少信号设备故障数量可归因于对新信号设备的大量投资、有针对性的干预以及远程状态监测所产生的益处，这些监测可以在问题之前发现问题。成为失败。当然，人们还必须把辛勤工作和注意力放在所有相关人员的细节上。整体表现不佳，以及媒体报道问题增多无疑是列车服务数量的增加，以及列车上乘客人数众多的原因。因为只需要一个信号失败，互联网推特上立即充满了延迟的列车的消息，或者其他形式通知全球"信号故障"！
作者点评：
“信号故障”是全球的轨道交通行业的话题，对公众而言很难搞清楚“信号故障”具体的含义，本文对英国近几年信号故障的原因进行分析，对新的维护处理提出了解决的方案，文中道岔故障，轨道故障的高发和我国信号系统故障如出一辙，我国大铁大力推行的“状态修”与英国铁路提出的预测和预防殊途同归，电缆偷盗在资本主义国家也是顽疾，人性不分国界制度，随着我国经济的大力发展，人民生活水平的提高，铁路运营封闭化管理，在我国偷盗已经不那么严重，随着铁路在制度、技术各个方面的不断完善，我国铁路已经步入世界强国，铁路发展永不休！