Close the rail line
Close the rail line and replace with light rail
Upgrade the line, by duplication in key sections
Upgrade the line, then extend it out to Point Cook
Run the Geelong line back unto the Werribee corridor and uses Metro 2 tunnels, Werribee uses the Altona loop (which is upgraded) and Williamstown use existing route
Leave it as it is
I used to think it was a great idea to utilise the growing area of point cooke so the Altona line doesn't need a downgrade for its lack in patronage. The problem is extremely expensive and other projects are much more priority over this.
I don't think closing the line is great option because like the Upfield line it can be used to divert services. Personally I am in favour of C and then eventually to option E when the opportunity comes.
Note Options A-C are medium term and D and E are much for long term investments.