The route is locked when the approach section(s) turns from vacant to occupied. If the DelayedLock timer is not given (or zero), the lock applies immediately. The route approach lock can apply to: <ul> <li>an entry signal: the proceed aspect of the entry signal is locked.</li> <li>a (set of) route(s): in this case the triggering mechanism depends on the kind of route, e.g. entry speed.</li> <li>a route body, in case the aspect of the entry signal or the properties of the route are irrelevant.</li> </ul>