题目

英语翻译
Metro Signaling and Modern Railway Signaling
Signaling used on high density metro (or subway) routes is based on the same principles as main line signaling.The line is divided into blocks and each block is protected by a signal but,for metro,the blocks are shorter so that the number of trains using the line can be increased.At first,metro signaling was based on the simple 2-aspect (red/green) system as shown in Diagram 8.Speeds are not high so three-aspect signals were not necessary and yellow signals were merely put in as repeaters where sighting was restricted.
Many metro routes are in tunnels and it has long been the practices of some operators to provide a form of enforcement of signal observation by installing additional equipment.This became known as automatic train protection (ATP).It can be either mechanical or electronic.
Electronic ATP includes tract to train transmission of signal aspects and (sometimes) their associated speed limits.On-board equipment

提问时间：2020-10-30

答案

地铁信号和现代铁路信号应用于高密度的地下铁道（或者说地铁）的信号是基于和主干道信号一样的理论的.线路被分成几块而每一块由一个信号保护.但是,对地铁来说,区块之间的距离更短以使得使用这条线路的列车数量得以增...