VRIOGS 010.7 RevA - Public Transport Victoria

VRIOGS 010.7 Revision A 178. Track insulation should be designed to use the minimum number of insulatedjoints needed to comply with all other requirements.9. In complex areas track insulation should be designed using large-scaledrawings of the actual point and crossing work. Even with careful designsuch drawings may fail to accurately reflect the relative positions of items ontrack; consequently complex bonding layouts which appear feasible on papermay be unmanageable in the field and should be avoided.10. Designs using complex, multi-branched track circuits are not acceptable - anytrack circuit which branches three or more ways shall be subdivided into twoor more simpler track circuits.11. For bonding at ‘V’, ‘K’ and all points crossings, rail bonds should always betwo (2) rail head bonds; and welded to the outer head of the running rails inaccordance to Plan STD_G0097 Cross Bonding Typical Arrangement-Electrified Area, Plan STD G00154 Track Circuit Bonding at Points andCrossings, Plan STD G0153 Typical Arrangements of Bonding at Points andCrossings and Plan MS97/0730 Arrangement of Bonds for Tangential Points.6.4 Cross (Tie-In) Bonding1. Cross bonding between track circuits on adjacent tracks is used to distributethe traction return current over the maximum number of available conductors(rails) thus reducing the resistance between the train and the substationbusbar and reducing touch potentials. Note: due to the design or switching ofthe feed circuits; traction return current from trains on each side of a crossbond location may flow, to either the nearer or the more remote substation.2. Cross bonds shall be as short as possible and tie-in points shall be as near aspracticable directly opposite each other on parallel tracks.3. In open track areas, tracks shall be tied-in at substations and sectioning huts,with cross bonds as per Table 4 and Table 5.4. Cross bonding between substations and tie stations is normally designed tocarry one third to one half of the traction return current generated on one trackto the parallel track(s). In fault conditions the cross bonding may have to carrythe full traction load.5. Cross bonds should be placed close to stations where trains stop inpreference to mid section.6. The dimensions of cable, type of cable to be used and the methods ofconnection and installation are detailed in Section 9.0.7. Tie in and similar type bonding cables from tracks to either tie or substationsmust be installed as under track crossings and in accordance to VRIOGS012.2 Specification for Signalling Supply, Construction and Installation.8. The following tables identify where it is recommended that cross bonds beinstalled.a. Between any two substations separated by less than 5.0 km, theaverage and maximum distances between cross bond locationsdepends on the minimum main line rail type and must not exceed thevalues given in the following table: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.