Track-circuited

In recent issues two replies have been given to correspondents concerning the function of the diamond-shaped enamelled white plates fixed to signalposts, which are to indicate to enginemen that the section of line is track-circuited, so that action under Rule 55 of the Rule Book is unnecessary.

Some 60 miles of single line (with long and short crossing loops at suitable intervals) will be continuously track-circuited and colour light-signalled under the control of one signalbox at Llandrindod Wells, enabling 18 existing signalboxes to be closed.