The "Auto" train of the South Devon Railway with cab car "Kingfisher" and shoving 0-6-0 PT steamloocmotive # 6412 is entering Buckfastleigh from Totnes Riverside. During entry, the train driver deposits the token, which is attached to a ring, in the catching device provided for this purpose. The South Devon Railway uses the electric token safety system manufactured by Webb and Thompson. Each single-line section is provided with a pair of token instruments, one at the signal box at each end. A supply of identical tokens is stored in the instruments, which are connected by telegraph lines. A token can be removed from one instrument only if both signalmen co-operate in agreeing to the release. Once a token has been removed, another cannot be removed until the token which is "out" is replaced in either instrument. (There are variations on this sequence of events.) By this means, it can be ensured that at any one time, only one token is available to be issued to a driver. Tokens belonging to adjacent sections have different configurations to prevent them being inserted into the wrong instrument.
