Unfortunately this board has no "LIKE" button to acknowledge Neil's comments.
By now it should be realised by all that I am an enthusiastic supporter of viable rail, and some marginal stuff as well BUT I also recognize that the South Line presents particular problems.
Some of the problems are simply NIMBY combined with a sense of exclusiveness (see Mitcham Council) we don't want other peoples trains in our area.
Some problems are more imagined than real, people feeling a bushfire being held up by a train; there are alternate routes, there are cost effective solutions.
General train noise, no worse than B double on the freeway with exhaust brakes on
But the wheel squeal is a penetrating issue. The noise carries far beyond the track and close to the track, even at SASMEE, has sound pressure levels which cause pain. There is only a slight curve at SASMEE and that has recently been re-aligned but some wheels squeal. This noise pollution and in any other industry would attract a notice followed by a non compliance fine from DEWNR.
It is not beyond the capacity of modern technology to do something about it certainly in terms of detecting offending wheel sets and vehicles.
We have speed cameras linked to radar. Why not cameras linked to directional microphones tuned to the noise frequency. That way a squeal producing vehicle can be identified and the operators served notice. It would be significantly cheaper to implement than either building a long tunnel, the best option, or relocating the line across the ranges to the north. Who knows, identifying a noisy wheel set might even save a later derailment due to wheel failure?