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 ">信号后电话。一种位于信号上或附近的电话，在那里司机可以直接与发信人通信。也用于任何其他铁路工作人员的联系The control centre for signalling trains. This is where the signallers control the movements of trains by signals.
" class="glossaryLink ">信号箱．
