Exchanging the token

This short movie is to show how the "token" is exchanged from a moving train, to the signalman. On "single line" working, railways, there has to be a system, to safeguard the train on each section.... this is achieved by the signalman giving a "token" to the driver, before he proceeds into the next section....There is only one "token" for each section of single line working... and the token for the previous section cannot be use to continue the journey into the second or subsequent single line sections.... On the Watercress line, the first section is between Alresford and Ropley. The second section is Ropley to Four Marks. The third section is Four Marks to Alton...so when the train leaves Alresford, the driver has the "token", which ensures he is the only train on the section,.... on arrival at Ropley, he hands over the token to the signalman, (or his messenger), and pulls into the station.... If the train from Four Marks has arrived, then he will be given the token from Four Marks, so he can proceed,....if the train from Four Marks has not arrived, he must wait until it does... When the token is taken into the signal box, the actual token is put into part of the signal workings (like a key) and this enables the signalman to pull the signals and point to the "off" position, and the train can proceed. Now the Four Marks train will be given the Alresford token, and he can proceed to Alresford, where the token is collected by the signalman, as shown in the movie.....