We have the largest third rail network in the world, powering electric trains, and it’s mostly found on tracks in the South East of England
When we talk about the third rail, we mean the live rail which provides electric power to a train through a conductor placed alongside the rails.
Nearly half of the UK rail network is now electrified – and more than 30 percent uses a third rail to power the train.
How third rail works
Third rail systems are always supplied from direct current electricity. Trains have metal contact blocks (‘contact shoes’) which make contact with the conductor rail. Conductor rails are mostly steel (a specially conductive type).
Conductor rails have to be interrupted atlevel crossings, crossovers (a pair of switches that connects two parallel rail tracks) and substation gaps. Tapered rails are provided at the ends of each section, to allow a smooth engagement of the train’s contact shoes.
Electrical substations
Because the third rail is a very inefficient conductor (most of the electricity we put into it is lost as heat) we have to give the voltage a boost every mile or so and that’s why we have substations.
These take 33kv AC from our railway ring main, convert it to 750V DC and pump it into the rails.
Between these substations are Track Paralleling Huts (TP Huts) which are used for switching between electrical sections.
我们不得不安装许多新的变电站Thameslink Programmeto allow for more trains to run as the existing substations would have overheated and failed if we had run today’s services on them.
第三轨的历史
Third rail systems were installed from the 1920s onwards as in those days it was cheaper and more suited to metro operations. The last length of third rail was installed in the 1980s down to Weymouth.
It wouldn't be installed now as it is simply not safe enough for staff and there are considerable costs associated with the sheer number of Substations and Track Paralleling Huts required to keep the voltage from dropping too low to run trains.
你与火车活动
第三根轨可能是最困难的危险之一。它看起来就像一块普通的铁轨，但它带有750伏 - 很容易杀死你。流经的直流电流是您家用电力的三倍。它旨在向火车发送电力，但您是70％的水和完美的导体 - 它会拉开你，直到紧急服务能够关闭电源。
Research shows that in particular a large proportion of young people remain unaware of its potentially fatal dangers.
TheYou vs. Train由网络铁路和英国运输警察经营的活动亚搏彩票软件官网，瞄准青少年锤击铁路上存在的危险，无论像火车一样明显，还是隐藏在第三根轨道或轨道旁设施中的电流。
The only way to avoid these dangers is to never step foot on the railway in the first place.
第三根轨道和洪水
洪水可能会在铁路上造成问题。洪水可能导致基础设施的持久损害可能导致正在进行的修复工作，需要几天，周甚至几个月。
When flood water comes into contact with the third rail, it can produce steam –as seen in this video at Mitcham Junction。
An unusual amount of steam can be seen if the weather is particularly cold because the third rail acts as an immersion heater, so there is a temperature differential.
Heavy rain can overwhelm the drainage systems on the railway. When we pump rainwater away from areas with third rail, we always isolate it first.
我们的轨道员工工作和步行在第三根轨道旁边，作为其工作环境的一部分，他们训练有素，以便在它周围安全。
Find out more about洪水如何影响铁路and what we are doing to reduce it.
Keeping the workforce safe
Network Rail has a clear safety vision:365亚博 。导体铁轨安全围绕我们的员工设计，他们培训训练赛道。
对于我们的员工，在站点和周围的工作人员走路，第三根轨道被踢球板守卫。当我们的员工在铁轨上工作时，他们可以使用在现场轨道上槽的黄色塑料防护装置。此外，还有挂钩，该开关，其手动从实时导轨和负短路设备中卸下电缆，在变电站中使用开关实现相同的结束。
The live rail is split into electrical sections that can be isolated from each other, while allowing power to flow to other parts of the railway. However, trackside workers are trained to assume the power is always live.
