Following earlier discussion here, I got all those national comparative suburban and interurban journey times (the ones that showed NSW trains to be the slowest in Australia) together and sent them off in a letter to the Minister. Unlike previous attempts where I got the usual platitudinous response from a PR type, this one must have had enough meat in it to get an input from engineering people and signed off by the Parliamentary Secretary. Possibly they were stung by the extreme comparison with Perth. If so, it's a good thing they're aware of it if they weren't before.
To cut a long story short, we're not going to get faster double deck operations any time soon because there are far too many infrastructure issues to resolve quickly. The interesting one for the interurban services is the large number of unprotected rural level crossings which apparently "heavily determine" line speeds in order to maintain good sight lines. There were other issues mentioned but this one seems to have the strongest bearing on operating speeds. I know some of these level crossings. They're scary to drive across.
The other very pertinent point (in view of the performance claims made by double deck advocates) is that they said that it was impossible to match the performance of those single deck trains in other states because double deckers are disadvantaged on acceleration, deceleration, braking and dwell times. I'm normally sceptical of anything I'm told, but this aligns with my own previous conclusions. Double deckers are not cut out for urban commuter work but are an unavoidable necessity for longer distance, high-volume work where higher seating capacity is needed.
It will be interesting to see if anything comes out of Turnbull's offer of funding for interurban rail infrastructure to improve journey times. What concerns me, as one example, is that within five years there will likely be motorway all the way between Bomaderry and St Peters. It will take about 1 hr 30 mins to 1 hr 45 to drive that compared to 2 hours 45 on the train.