为驾驶员提供的一种系统，用于在驾驶室中提供视听指示驾驶室的状态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 ">信号在前面。该系统的工作原理如下：当列车接近信号机时，它会通过两个电磁铁（或一个永久磁铁（见下文）和一个电磁铁）放置在轨道之间的坡道。如果信号为绿色，两个磁铁都会被安装在车轴之间的接收器检测到。这会导致铃声响起，驾驶室中的警告盘显示为黑色。如果信号不是绿色，则只检测到一个磁铁发出喇叭声，并显示黑色和黄色。在这种情况下，司机需要通过按下按钮来接受警告，否则会自动应用制动器来停止列车。
