FFF公司

第一灯丝故障：指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

为安全起见，有一个以上灯丝的灯。灯泡必须更换，但信号机工作正常，无需列车警戒。