Kingsgrove to Earlwood Rail Electricity Supply REF (pdf 1.6MB)

4.2 Proposal AlternativesDo Nothing AlternativeThe ‘do nothing’ approach would result in the network no longer being able to support thepower requirements of the rail system. This would create instability in the rail network’spower supply and would adversely affect the public who rely on its services. As such, the ‘donothing’ approach is not considered a viable alternative for the proposal.Alternative Upgrade optionsA number of upgrade options were investigated. These included buried cables and retensioningof wires. However, these were discounted as these alternatives were not as costeffective and may require the construction of a new feeder rather than its replacement, whichwould result in an increase in environmental and community impacts.Alternative RouteNo alternative feeder routes were considered as the proposed route remains within the railcorridor between the Kingsgrove Substation and Earlwood Switching Station. This isconsidered to be the optimal route because:It limits the environmental impacts to previously disturbed areas within the rail corridor.It is the most direct and cost effective route.Enables reuse of existing infrastructure4.3 Justification of Chosen OptionTfNSW defined the design and scope required for the upgrade of the feeder. Rather thanfollow a buried Galvanised Steel Trough (GST) cable route the power study recommended there-tensioning of the existing Feeder 708 conductor wire. Following a Value for Money (VfM)analysis an upgrade of the feeder route was deemed to be the most cost effective solution.Although it is possible to change the feeder’s alignment and consider alternative routes thiswould have greater costs and environmental impacts. The construction works involve minorpole excavations undertaken within the rail corridor and these works will cause low level noiseand insignificant dust impacts on the surrounding environment.4.4 Construction MethodologyTable 3 identifies the poles proposed for replacement and those that will have pole topsrefurbished. Key elements for the construction of the proposed pole modifications willinclude:Replacement of existing aerial 33kV at Earlwood Substation to Under Ground Overhead(UGOH) Pole 40 on country end of Kingsgrove Avenue.Replacement of existing overhead wiring (OHEW) to eliminate impact of galvanic corrosionwhen bare copper conductor is over aluminium alloy conductor (AAC).Extend OHEW for 275m (approx) between poles 27 to 30 where none presently exists to giveOHEW protection throughout the length of the feeder.Page 21