我们有20,000英里追踪，这意味着我们有很多钢铁轨道。
Withdemand for train travel doubling in the past 20 years, its maintenance and renewal keep us busier than ever.
我们的工程师始终改善铁路后的照顾。用轨道，这意味着在他们出现并确保其对乘客和货运列车安全之前，我们最好地防止像破碎或扣上的铁路一样的问题。
这些问题如何发生，我们如何尝试阻止它们？
平均而言,我们记录约100 rails是的折断r – a huge decrease from 20 years ago, when we recorded more than 900 in one year. Broken rail incidents exceeding 700 a year were typical in the 1980s while figures of 600 and up were common in the 1990s.
Achievements in reducing the number of broken rails each year have come despite a surge in rail travel – and less access to track for our engineers.
Broken rails can occur because of a small defect in the rail or where the rail is subject to excessive loads. Small defects can grow under repetitive loading – more than three million axles (part of a wheel) pass over the rail every year on a busy mainline.
想象一条电线衣架 - 你可以弯曲它，但如果你这样做太多，你会削弱金属。它与轨道相同 - 它具有一定的强度和延展性。在寒冷的天气中使用的一些轨道强度，因为轨道紧张，因为它被压力，以防止在炎热的天气期间屈曲。
Stressing is required to enable the rail to cope with different temperatures in different seasons. Due to the high forces exerted on the rail in service defects need to be identified and removed before they reach a critical size and the rail is at risk of failure.
为什么我们压力轨道？
In engineering terms, stressing is a good thing – it helps us keep the railway safe in很热或非常冷的温度。
In case a British summer features abnormally high temperatures, we must plan for intense heat, which can cause rails to expand. Where the compressive forces in the rail reach a critical point, the track can suddenly distort sideways, causing a buckle if it is not restrained sufficiently by the ballast around the sleepers.Read more about why we stress rails to prepare for hot summers.
If we plan to stress rails, why do rails sometimes break?
We work hard to keep a close eye on the entire railway but sometimes, incidents happen. Usually, it’s because something has unfortunately failed in our process.
我们调查了这一事件，并提出了为什么发生，以及我们如何改变我们的流程，以防止它再次发生。
How do we fix a broken rail?
在简单的情况下，我们可以夹住破碎的轨道并告诉火车慢慢降低 - 被称为临时速度限制 - 直到我们可以发送工程师永久解决问题。这限制了乘客的中断。但是，它并不总是可以执行此操作 - 例如，如果断裂太大或以一定角度而无法安全夹紧。
一块轨道上的破碎导轨 - 被称为普通线 - 更容易修复，因为它很简单地用短长度的新导轨更换。
它通常是铁路的位置，使得修复更难以修复 - 像架子加工轨道或专门设计的流动交叉都建立了开关和交叉等部件。这是专门设计和制造的轨，为该精确的位置设计。
Why? First, because some places have more complicated sections of track in junctions. Second, because much of our railway is old and designs have been changed over time to improve reliability and performance.
This means we can easily and quickly fetch a replacement piece of rail for plain line track but we must often manufacturer a replacement for bespoke track, which takes time.
画廊：我们的特殊公路铁路车辆（RRV）固定破碎的轨道和焊接新轨道
If a rail breaks on one line, why does it delay trains on the lines next to it?
我们知道延误令人沮丧，我们尽我们所能避免他们，但我们必须始终平衡风险。
安全是至关重要的 - 当我们将我们的团队发送到追踪修理一块铁路时，我们必须在他们周围创造一个安全的环境。越来越多地，这意味着在他们正在处理的线上给予它们更多的空间，这可能需要对相邻线上的速度限制。
For complex switches and crossings, a broken rail may affect multiple lines, preventing trains from passing from one track to another.
How are we improving?
As well as improving our processes for safety, we’re working towards a more standardised railway so that in future, we will be able to run a railway with far fewer bespoke sections of track.
这将意味着我们可能会使用3D打印来制造更换组件，以及当我们需要它时 - 在汽车和航空航天领域中有望变得更加常见。
我们目前保留一定数量的备用轨道和交换机和交叉部件进行维修，但英国铁路有20,000英里的轨道和超过19,000个连接，所以我们不能保留备件。
Meanwhile, we’re significantly improving the technology we use to monitor the condition of rail across the country. One of the things we do is ultrasonically test rail – big yellow trains fitted with complex test equipment that emit high frequency sound into the rail at different angles to look for small cracks inside the rail.
我们也使用普通线模式识别技术（PLPR）in combination with track geometry measurement, which dramatically increases our capacity to monitor, inspect and fix track faults by analysing high definition imagery of the rails, fastenings, sleepers and ballast.
阅读有关PLPR的更多信息并观看此视频以了解更多：