Gauge convertible concrete sleepers would not have reduced the train speeds if only the broad gauge rails were installed, the restricted speeds for broad gauge operations only apply if the standard gauge rail is installed for dual gauge operations, if the boffins at VR could show some foresight all sleeper replacements would be gauge convertible sleepers if preparation for the time when conversion to standard gauge is warranted.
Meanwhile, Ballarat to Ararat won't be going SG anytime soon with 10000s of sleepers now of the BG concrete variety.
It's important to realise that dual guage sleepers would have reduced the speed of trains to 100Km/h or worst case, 80Km/h.
Dual gauge sleepers and gauge convertible concrete sleepers are two different beasts.
DG sleepers are designed for permanent use on dg track sections which in Victoria currently allow line speed for sg trains, and 80kmh for bg trains, however it is understood VLP has proposed 100kmh on the currently planned dg track section Maryborough - Ballarat for bg trains.
Gauge convertible sleepers have two sets of fittings for affixing the rail on one side. In the Victorian application of bg/sg variation such sleepers should be used for all Victorian tie renewal works on all regional lines as of now. Then when one needs to standardize the line one just moves the rail inwards onto the second set of fixings.
The marginal cost involved in using gauge convertible sleepers now is marginal like a $ 1 or so extra cost per sleeper.
In the case of passenger/freight lines VLP should be using low profile gauge convertible sleepers which are readily available from Austrak (BUT to date V/Line has refused to even trial them), and on freight only lines gauge convertible steel sleepers which VLP also refuses to show any interest in using - albeit they have been hugely successful on NSW regional freight lines, and by ARTC recently between Yarrawonga and Oaklands.
So in the case of Wendouree - Ararat which will be ultimately standardized medium term it has just been sheer shortsightedness coupled with poor VLP attitude to gauge convertible low profile concrete sleepers that only low profile bg concrete have gone in - ultimately all these will have to be pulled out at much greater cost than the incremental extra cost of putting in the gauge convertible variant now, first up.