197503 – Harvey – Signalling Developments on the Victorian Railways at Oakleigh: Geographical Circuitry

The rapid expansion of railway signalling on the Melbourne Suburban mil system brought about, firstly by the Melbourne Underground Rail Loop project, and secondly by an extensive list of projects to be financed by the Commonwealth Government under its urban developments scheme, offered the opportunity to revise certain techniques previously used.

After 2 years of planning, research and development work, several new techniques have gone through various stages of proto type testing, and will be brought ,together in a medium size installation at Oakleigh for further “in service” evaluation before being committed to the larger installations in the Flinders Street Central area.

These techniques are:-
– A system of geographical circuitry for vital controls only.
– An electronic system using CMOS intergrated circuits for non vital route setting controls and indications.
– Use of Light Emitting Diodes for track indication diagrams.
– Adaption of the 0.R.B. clamp lock point machine to suit VR point layouts and operated by compressed air.
– Use of electro-pneumatic train stops, type Westinghouse J.A. similar to those used on the London Transport System.
– Use of high voltage impulsing track circuits of the Jeumont type in the single rail points and crossings arm, to achieve immunity from possible future thyrister control of electric trains.

(Items. 5 & 6 are not reported on in this paper).

The installation at Oakleigh replaced two obsolete mechanical signal boxes in conjunction with the completion of the automatic signalling on the Dandenong Line.

Oakleigh is an intermediate terminal station and this work is being carried out in conjunction with an extensive yard re-arrangement, to achieve improved terminal working, provide better access to the goods yard area and make provision for an ultimate 3rd track to Oakleigh.

Provision has been made on the track indication diagram and control panel for the ultimate remote control of all interlockings between Oakleigh and Dandenong (viz Huntingdale-proposed future junction to new branch line, Westall and Springvale).

The projection therefore achieves very significant progress in the development of the Melbourne Suburban Rail System.

Signal Diagrams of “before” and “after” are shown on figures 1 and 2.