In the 80's a major track rehabilitation started on the Hunter Valley line in NSW, this included the complete removal of the old track and old ballast, in cuttings both big and small, the whole of the formation under the ballast was taken back and prior to new and cleaned ballast being replaced, large sheets of drainage cloth was placed under the new work. Long sections were carried out, one line at a time, up then down lines but not always in that order. Sleepers en mass were replaced totally with cement sleepers and 63Kg rail, it took a couple of years to get the whole lot as far as Muswellbrook completed, that is now 40 odd years in the past, and travelling over the line a few times and its starting to show signs of wear especially the sleepers.
Since that original work was carried out rail has been replaced but not so much the sleepers, I travelled to Wickham yesterday 17/01/19 and back from Victoria St near Maitland, and this area was the first to be replaced those years ago, with trains now running with a lot heavier loads the whole lot gets a pounding, once thing for sure is that the only short length rails, at even 106lb on timber sleepers would hardly have stood up to the traffic that is seen today.
On the trip I took notice of how the sleepers have stood up to the years of work, looking at them from the pax service both directions and the sleepers on the Coal roads, almost every one of them showed a lot of signs of wear, in the sense that the original clear and smooth concrete surfaces were very much gone with evidence of the finer blue metal also very evident on them. What I also notice along the line within the boundary fences is quite a lot of stacks of old concrete sleepers, many very much cracked and broken I wonder how the detireating condition of those sleepers still in use can last as rail volumes are not going down.
On one of the News programs last night, and this shows that heat and the like still affects railway track, it showed a video of fire trucks in place at what looked like Mittagong, having been called out to hose down the rails in order to prevent the track from buckling, the water was being used predominately on the up track but also on the down line as well. During the video clip and news reader making the report a down predominately container train came through on the down hauled by 2x81cl, and they did not appear to be running at a reduced speed either.