198611 – Carey – Melbourne Metropolitan Signal Systems Review

This paper describes the review carried out by the S & C Department to establish a criteria to rehabilitate the Metropolitan signalling system to a defined standard of signalling to ensure the continuing safety of passengers, improved operating efficiency and maintainability of systems.

The train running capacity of each signalling system has been determined and the systems to be rehabilitated have ,ben identified. The Operations Department is to review their train running requirements as they relate to main line signalling and also the impact of the stabling decentralisation.

Remote control of rehabilitated areas is also proposed, and each line or group will ultimately be remotely controlled, in order to improve operating efficiency. In the longer term, all remote control will be centred at Metrol.

The paper also proposes the direction that Signal and Communications technology is to take over the ensuing years, and also suggests a signalling methodology for the future.

It is proposed that the Metropolitan signalling system will be rehabilitated to a defined level of safety and operational efficiency. At this time the defined level does not include cab signalling or computer aided ‘on board’ braking, train description or automatic route setting. It is proposed, however, that a foundation be provided to introduce these technologies at the appropriate time.

The various levels of Multiple Aspect Speed Signalling (M.A.S.S.) systems have been defined and categorised as follows:
Level 0 – Mechanical Systems Interlocking.
Level 1 – Elec/Mech Systems Interlocking inc. Semaphore signals.
Level 2 – M.A.S.S. (Shelf Relays) with Relay System Interlocking.
Level 3 – M.A.S.S. (Large Relays) with Relay System Interlocking.
Level 4 – M.A.S.S. (Min. Relays) with Relay System Interlocking.
Level 5 – Multiple Aspect Speed Signalling (Phase Independent) with Relay or Computer Interlocking Jointless track circuits and Clamp Lock point mechanisms, and includes electro-hydraulic train stops.

It is believed essential that Mechanical Signals, Electro Mechanical Signals and Semaphore Signal systems (Level 0 and Level 1) should be replaced urgently because of age maintainability and safety concerns.

Relay interlocking using shelf and large relays should be progressively replaced by way of their age, replacement, part availability and their inability to be remotely controlled (Level 2 & 3).

Signalling systems that are phase dependent (Level 4) is restrictive and expensive to rehabilitate. Upgrading of the signalling power supply and rehabilitation of wayside signalling equipment should be progressively carried out.

The present signalling standard (Level 5) has evolved over a number of years and incorporates system design that reflects the railway environment, and also track conditions. In addition, it allows for future development such as automatic train description, automatic route setting, cab signalling and auto train protection to be incorporated in due course.

The paper relates also to the development of signalling for efficient train management and control by implementing individual group operation of the metropolitan rail network.

The rehabilitation is designed to accommodate future expansion such as Automatic train protection and cab signalling to optimise traffic densities, higher train speeds, less wear and tear of equipment and energy savings.

The benefits from further signalling development and upgrading above level 5 that can be readily identified are listed below:
– Increased safety of passengers, by A.T.P. (automatic train protection).
– Improved train information and consequently train management will be available to train operators, using train description method.
– Statistical reports available for management information and forward planning from extended train describer.
– Improved equipment reliability with lower level of field maintenance. Improved response to failures due to centralised signal maintenance fault diagnostics with remote control of train describer.
– Scope for operational staff savings account centralised control and automatic operation.

The deficiencies of the existing signalling systems which can be readily identified are:
– Aged and obsolescent equipment and shortage of spare parts, which reduces system reliability.
– Maintenance intensive electromagnetic equipment.
– High Voltage Signal power system arrangements which, as the only signal power supply, is intrinsically unreliable.
– Operationally labour intensive due to number and arrangement of signal boxes.
– Inflexibility of the existing signalling system which precludes changes for increased operational efficiency.
– Irregularities or failures on any one region impacting on the train performance of other regions.
– The scope to introduce reliable cost effective new technology to cater for the changing needs and demands of users of public transport is significantly reduced.

Rehabilitation could be carried out over a seven (7) year period if funds are available and in conjunction with other projects. With due regard and equal importance to all other projects, Signalling Rehabilitation Project as defined could be implemented utilising a mix of in-house and external resources.