I would say that we should convert diesel truck freight to diesel rail freight, if that gets us the most bang for buck.

(I was pleased to discover today that they are actually triplicating 'my rail line' at the moment after looking up what all the heavy machinery was doing I saw on the train home today.  This means the possibility of electrifying freight to eastern Vic, but only if they switch from the 1910 era 1500DC to a modern 25kVAC.  I'm pleased anyway that they are actually spending useful amounts of money, and getting rewarded - regional rail has doubled ridership in the last 2 years, and is limited by available seating rather than demand!)