VRIOGS 010.7 RevA - Public Transport Victoria

VRIOGS 010.7 Revision A 9SECTION 5.0NON-ELECTRIFIED TRACK AREAS5.1 GeneralWhere non-electrified tracks run in the vicinity of electrified tracks, the extent of theinfrastructure provision needs to be determined. Within this area three situationsexist.1. Electrified Tracks: tracks are electrified to allow electric trains to run from theelectrified area to some point on or connected to the non-electrified track andmust provide a return path for the electric traction current which is acceptablefor the normal operation of electric trains.2. Non-Electrified Tracks in Electrified Area: tracks that are non-electrifiedbut electric traction faults may inject fault current into the non-electrified railsand a return path for the electric traction current.3. Tracks in Immunised Area outside Electrified Area: tracks that are nonelectrifiedand subject only to the effect of stray currents coupled into thetracks or line-side circuits from the traction current circuit.5.2 Extent of ProvisionsGenerally signalling infrastructure within an electrified area and for some distancebeyond must be immunised from the effects of the electrification.1. Where non-electrified rails are used by electric trains (example being overpoints and crossings), provision for normal traction current return must bemade. In such cases the design of the rail bonding shall be based on makingthe impedance of the return path as low as practical to minimise tractionsupply losses, overheating of equipment and voltage build-up along the railsboth from the DC and harmonic components of the return current.2. Where the non-electrified rails are not used by electric trains, provision fornormal traction current return is of no advantage to non-electrified lines;therefore it is preferable that provision for traction fault current only be made.In this case the design of the rail bonding shall be based on making theimpedance of the fault current path such that voltage build-up does not reacha harmful level for either the equipment or any personnel in contact with therails.5.3 Electrified Tracks1. Wherever electric trains may run over non-electrified tracks the infrastructureshall make full provision for traction current and in accordance with thisspecification; including traction current bonding of the rails and immunisationof all signalling equipment against both traction return and stray currents.2. Where the electric traction supply system terminates whilst the rail corridorcontinues the full provision for traction current shall extend at least oneelectric train length beyond the last point at which an electric train tractioncollector could make contact with the supply system.NOTE: This document is controlled only when viewed on the DOT Engineering Standards website.Any other copy of this document is uncontrolled, and the content may not be current.