Edited sentence: However, in some cases, Train Controllers were appointed at key signal boxes, obviating the need for telephonic communication.In New South Wales, Australia, Train Controllers and the Telephone Train Control System have survived to the present despite the advent of power signal boxes.In some cases, a Traffic Regulator or Supervisor is appointed, who may be consulted for train working decisions.In the UK, the beginning of the end for classic "Control" came with the commissioning of large power signal boxes from the 1950s.It is difficult to ascertain whether these changes have led to an overall improvement in train working efficiency or have merely ensured the survival of the Train Controller's profession by means of fabricated, duplicated, diversified and rearranged responsibility.It is important to note that while Train Controllers made train working decisions, they had no safe working or signalling responsibilities, which were within the realm of the Signalmen and Station Masters.No statistics on this matter are available.The power signal box (PSB) has a number of Signalmen operating multiple electric or computerized signalling panels and large illuminated track diagrams showing wide areas of operation.These Train Controllers have gradually assumed some theoretical and actual safe working responsibility, to the extent at which they do occasionally make safety-critical decisions which are then executed by Signalmen.This makes traffic regulation much easier for Signalmen to handle among themselves.This method of operating was known as the Telephone Train Control System.Typically, Train Controllers were stationed at district control offices which were linked by omnibus circuit telephone systems with selective code rings, to all signal boxes in the area