Claering up two myths :I agree that there is a case for the government to buy some trailer cars but as far as I am aware they have no plans to do that. I am a bit puzzled that when you think that running 9 car trains isn't practical you would be ok with an 8 car train. On thing is certain, with capacity constraints on the regional line from Southern Cross to Sunshine/Deer Park there isn't much scope to run many additional 6 car trains.
- The single track section section Geelong - South Geelong is NOT the issue it is only 3 mins run time .
The service reliability issue is the lack of double track between South Geelong and Waurn Ponds . The round trip run time Geelong - Ponds including tight turnaround is 40 minutes, so existing off peak pattern dicates every 40 to the Ponds and every 20 to South Geelong . Works pretty well, but very tight at peak times with trains fleeting through to South Geelong, Ponds & Marshall .
- The duplication cost is more like $ 300m , and the grade seps add another $ 400m . Wood St is to grade separated probably as that route offers the only East/West route across Geelong for truck traffic . Surf Coast Highway is major divided road with huge traffic volume .
- 9 car VL trains will not happen fast for three reasons 1. Extremely expensive capex wise and opex wise 2. Would actually reduce peak hour train throughput at Southern Cross and 3 . number of operational issues associated with platform extensions to 9 cars and signals etc . (9 car VL trains would take up all of plats 2, 3, 7 or 8 or 15/16 and reduce remaining platform faces available to other train sizes.)
However 7 car VL sets to both Geelong and Ballarat would be easy . Simply buy 28 - 30 trailer cars and insert into 28 - 30 of the 88 VL set fleet . Then one can run VL train sizes of 3, 4, 6, 7 or 8 cars . By simply acquiring 28 - 30 VL trailer cars to make a mix of 3 and 4 car sets the peak hour capacity over 1530 - 1830 on both Geelong and Ballarat can be increased by over 30% for marginal extra opex at lowest capital cost per extra seat . The issue now is LONGER V/Locity trains, not more 3 car VL trains .
88 VL total train sets is more than enough to operate all VLP train services . In fact with short term electrification to both Wyndham Vale and Melton there will be VL 3 car sets released for use elsewhere .
I'm not sure what you mean by short term but I wouldn't expect to see an electric train at Melton or Wyndham Vale for another decade. Once deliveries are complete the 88 Vlocity sets will be fully utilised by replacing loco hauled sets, increasing some 3 car workings to 6 car & the sheer volume of passenger growth. Even after electrification it's hard to see that there will be any spares.