4 interlocking principles4 连锁规则4.1 safe routes through an interlocking4.1 安全进路通过一个联锁The term “interlocking”is used with two meanings. First, “an interlocking”is the interlocking plant where points and signals are interconnected in a way that each movement follows the other ill a proper and safe sequence(see Section 1.2). Second, the principles to achieve a safe interconnection between points and signals are also generally called ”interlocking”.“联锁”的概念在使用中有两个意思。
第一，“联锁”是指连锁设备。
如道岔和信号机，以这样的方式相互关联，每一个动作受约束与另一个（动作），来保证合适而安全的结果（见1-2段）。
第二，为了达成在道岔和信号机之间的安全互联而存在的规则也通常称为“联锁”。
The route a train could use through an interlocking must meet the following conditions：列车可以使用的通过联锁的进路，必须达到一下的情形：⏹All points must be set properly and locked,⏹所有道岔不许被设置在合适的位置，同时被锁闭，⏹Conflicting routes must be locked,⏹抵触进路必须被锁闭，⏹The track must be clear.⏹线路必须出清。
This is provided by the following functions:这些要求可以由以下功能提供：⏹Interlocking between points and signals,⏹道岔与信号机之间的联锁，⏹Route locking,⏹进路锁闭⏹Locking conflicting routes,⏹抵触进路锁闭，⏹Flank protection,⏹侧面防护⏹Track clear detection.⏹轨道线路出清检测On railways where the signals for train movements are separated from those for shunting movements (main and shunt signals), the interlocked routes for train movements are also considered separately from those for shunting movements. Some of the requirements for a train route are not in effect for a shunt route. So, a shunt route may govern a shunting movement into an occupied track. And, flank protection (protection against inadmissible movements on converging tracks) is usually also not required for shunt routes. There are also railways, where interlocked routes are only required for train movements, while shunting movements are carried out without protection by the interlocking system. This is especially typical for ancient German interlocking systems. On North American railways where train movements are not as strongly separated from shunting movements, the same interlocked routes may be used both for train and shunting movements. A train route starts always at an interlocking signal (the entrance signal of the route). The exit of a route can be:在轨道上，列车运行的信号与调车运行的信号是区分开的（主信号与调车信号）。
列车运行的联锁进路也被认为是与调车运行的联锁进路相区分的，列车进路中的某些要求在调车进路中是无效的。
所以，一个调车进路可以控制一个调车运行进入一个已被占用的轨道区段。
同时在调车进路中侧面防护通常也不被要求。
（侧面防护：为禁止在汇合轨道上的不被允许的列车运行而进行的防护）。
也有一些轨道交通中，联锁进路只在列车运行中被要求，而调车运行可以在无联锁系统防护的情况下执行。
这在以前德国联锁系统中是很典型的，而在北美的轨道交通中，列车运行与调车运行的区分并不是很清晰，列车与调车运行可以使用同一个联锁进路。
一个列车进路的始端通常是一个联锁信号机（入口信号机或进路）。
而进路的终端可以是：⏹Another interlocking signal (the exit or destination signal of the route),⏹另一个联锁信号机（出口信号机或目标信号机）⏹The end of the interlocking or home signal limits.⏹联锁区段的终点或是进站信号机界限Interlocked routes with an entrance and an exit signal are routes between successive interlocking signals within the same interlocking or home signal limits (see Section 1.2). On railways where overlaps are required, even the points within the overlap behind the exit signal will be interlocked to the entrance signal (Figure 4.1 a). Because the clearance of the section between the entrance and the exit signal is checked by the interlocking system, this kind of an interlocked route also directly ensures a safe train separation. Thus, there is no need to install a block system between these signals.有入口和出口信号机的进路是在连续的连锁信号机之间的进路，这些信号机有同样的联锁或进站信号区域（见1.2段）在有重叠的轨道区段，在出口信号机之后重叠区段内的道岔也要与入口信号机相联锁，因为在入口信号机和出口信号机之间的轨道区段的出清检测是由联锁系统进行的。
这种联锁进路也直接确保了安全列车间隔，所以这些信号机之间不必再建立闭塞系统。
Interlocked routes with tile exit at the end of the interlocking or home signal limits govern train movements to leave these limits. Such a route cannot ensure a safe train separation. The route leads into a section of line that may be protected by a block system or by written or verbal instructions. On North American railways, the route will always end at a controlled signal facing in the opposing direction that limits the interlocking (Figure 4.1 b). Sometimes, this signal is called an “exit signal”at interlocked routes between adjacent interlocking signals of the same direction as explained above. On European railways, the exit of the route is a track section behind the last points of the route. As an essential difference to North American practice, this track section is not necessarily Associated with an opposing controlled signal.在联锁信号或或进站信号区域末尾的地方有出口指示的联锁进路会控制列车运行通过这些区域。
这样的进路无法保证安全列车间隔。
这种进路的结果是使线路的一个区段，由闭塞系统或由书面与口头知识来保护，在北美的轨道交通中，进路的终端通常是一个面向反方向的受控信号机，这样来分界联锁。
有时，这样的信号机被称为一个“出口信号机”，但是这个名称不应该与另一个“出口信号机”的用法混淆。