彩色光Visual indication passed to a train driver to advise the speed, direction or route of the train. There are almost as many types of signals as there are railways but they fall into the following main categories:1) handsignals - used mainly where there are no fixed signals or where the fixed signalling has failed. 2) semaphore signals - a fixed lineside signal where the stop indication is displayed as a horizontally positioned arm and proceed as a 45º or vertical arm. 3) colour light signal - a fixed lineside signal showing light indications to drivers. 4) cab signals - where the indications are displayed in the driver's cab.
" class="glossaryLink ">信号能够显示四个方面。从上到下灯光，绿色，黄色和红色。红色指示意味着下一个部分包含火车。单个黄色指示（使用较低黄色）意味着下一部分是清晰的，但下面有一个列车。双黄色指示意味着接下来的两个部分很清楚，但是一个超出它的火车。绿色表示接下来的三个部分很清楚。根据火车的速度，它需要开始在单个黄色或双黄色上放慢速度。
