THE SIGNAL BOX

OVERSEAS

MERREDIN
Western Australia Government Railways

by John Hinson

Merredin signal cabin
Photograph by Dr J W F Scrimgeour

Merredin signal box stood on wooden piles on the island platform of the station by that name, which was situated about half-way between Perth and Kalgoorlie.

Interior of Merredin cabin
Photograph by Dr J W F Scrimgeour

The cabin was large by Western Australia standards, containing a 95-lever McKenzie & Holland lever frame. However, by the time of these photographs, about half of the levers were out of use and painted white.

Interior view of Merredin cabin
Photograph by Dr J W F Scrimgeour

This view shows the clutter of equipment in back wall of the cabin. Starting at the left, a full-size Electric Train Staff instrument, then the signalman's desk with the train register and an array of telephones. Beyond the table, chair and sink is the special switch for staff working, described below.

Special switch for automatic staff working
Photograph by Dr J W F Scrimgeour
Electric Train Staff instrument at Merredin
Photograph by Dr J W F Scrimgeour


Above right is one of the Electric Train Staff instruments, built to the design of the London & North Western Railway in the UK but manufactured under licence by the Railway Signal Company for use on other railways. This type (known locally as "staff columns") was extensively bused on single lines in Western Australia, although in other parts of the country the "miniature" version was more common.

Above left is a switch unit used to control whether Manual or Automatic staff operation is operating. When an intermediate box is closed, Automatic working allows the signalmen in the adjacent boxes to withdraw a staff without a release from the intermediate box. The method of operation would have been similar to that described at Polona Crossing in New South Wales. Train crews would operate the staff instruments themselves at the closed box. Above the switch is a Sykes' indicator, which was probably manufactured in Australia by McKenzie & Holland under licence.

A similar arrangement was introduced on the Festiniog Railway in the UK. This was devised by somebody who had worked in Australia, so the way it worked was probably similar. The Festiniog system requires the signalman to wind a generator, which puts AC current on the line-wire to the staff instrument at the other end of the section. At the remote end, an AC-sensitive relay operates a simple circuit that, once the signalman stops winding the generator, has the same effect as a signalman there plunging for a few seconds, allowing time for the token to be withdrawn.

Although closed some years back, the box at Merredin still stands and can be accessed by visitors.

Additional notes by Chris French and Peter Matthews


Comments about this article should be addressed to John Hinson