英语翻译Signal A2 shows the condition of Block A2,which is occup

英语翻译
Signal A2 shows the condition of Block A2,which is occupied by Train 1.If Train 2 was to overrun
Signal A2,the raised trainstop (shown here as a “T” at the base of the signal) would release its emergency brake and bring it to a stand within the overlap of Signal A2.
Overlaps are often provided on main line railways too.In the UK,it is the practice to provide a 200 yard (185m) overlap beyond each main line signal in a colour light installation.In the UK,the overlap is considered so important that a whole block is provided as the overlap.
Track-Circuited Overlaps
Nothing in life is as simple as it seems and so it is with overlaps.A line which uses overlaps and has close headways could have a situation as shown here where the train in the overlaps of Signal A1 has a green signal showing behind it.Though it is protected by Signal A2 showing red,the driver of Train 2 may see the green signal A1 behind Train 1and could “read though” or be confused under the “stop and proceed” rule(Diagram3).
So,where there is a possibility of a green signal being visible behind a train,overlaps are track circuited as shown in Diagram 4.Though there is no train is occupying the overlap track circuit.This will give rise to two red signals showing behind a train while the train is in the overlap.
Automatic Train Protection
To adapt metro signaling to modern,electronic ATP,the overlaps are included into the block system.This is done by counting the block behind an occupied block as the overlap.So in a full fixed block ATP system,there will be two red signals and an unoccupied,or overlap block between trains to provide the full safe braking distance,as shown in Diagram 5.By the way,many ATP equipped system do not have visible lineside signals because the signal indication are transmitted directly to the driver’s cab console (cab signaling).
On a line equipped with ATP as shown above,each block carries an electronic speed code on top of its track circuit.If the train tries to enter a zero speed block or an occupied block,or if it enters a section at a speed higher than that authorized by the code,the on-board electronics will cause an emergency brake application.This is the system used by London Underground for the Victoria Line from 1968-the first completely automatic,passenger carrying railway.It was a simple system with only three speed codes-normal,caution and stop.Many systems built since are based on it but improvements have been added.

信号A2 显示块A2 的情况,乘火车1 占领.如果火车2 将侵占 发信号A2,被上升的trainstop (被显示这里作为"T" 在信号的基地) 会发布它的紧急制动器和会带来它给一个立场在信号之内A2 交叠.交叠经常被提供在主线铁路也是.在英国,这是惯例提供200 码(185m) 交叠在各条主线信号之外在颜色光设施.在英国,交叠被认为很重要,一个整体块被提供作为交叠.轨道巡回的交叠 没什么在生活中一样简单象它似乎并且因此它是以交叠.使用交叠和有接近的进展的线依照被显示能有情况这里何处火车在信号A1 交叠有一个绿色信号显示在它之后.虽然它由Signal A2 保护显示红色,火车2 的司机也许看绿色信号A1 在火车1and 之后能"读虽则" 或是迷茫的在"中止之下和进行" rule(Diagram3) .如此,有一个绿色信号的可能性是可看见的在火车之后的地方,交叠是轨道巡回依照被显示在图4 .虽然没有火车占领交叠轨道电路.这将提升二个红色信号显示在火车之后当火车是在交叠.自动火车保护 适应地铁发信号现代,电子ATP,交叠是包括的入块系统.这由计数做块在一个被占领的块之后作为交叠.如此在一个充分的固定的块ATP 系统,有将是二个红色信号和一个没人住,或交叠块在火车之间提供充分的安全刹车的距离,依照被显示在图5 .顺便说一句,许多ATP 被装备的系统没有可看见的lineside 信号因为信号征兆被传达直接地给司机室控制台(小室信号) .在线被装备ATP 依照被显示以上,各个块运载一个电子速度代码在它的轨道电路顶部.如果火车尝试进入零的速度块或一个被占领的块,或如果它比那输入部分以速度更加高级由代码批准,在机上电子将导致一种紧急制动器应用.这是系统由伦敦地下首先使用为维多利亚线从1968-the 完全地自动,乘客运载的铁路.这是一个简单的系统以只三速度代码正常,小心和中止.许多系统被建立因为根据它仅改善增加了.