One of the most complex yet common challenges in a project like this one is that rail lines have to be extremely flat. As surveyors bring their assessments in, you'll discover that the Toowoomba ranges are anything but – full of hills, valleys and floodplains, they present a significant challenge to engineers whose jobs it is to get a train moving smoothly and safely along this part of the alignment.
Check out the video below, which details why trains struggle to go up steep gradients 🚂 ⛰
So, if can’t go over the hill, what's our option?
Simple – go through it. Rail tunnelling is used to effectively punch a hole through the hill at a flat alignment. This process is highly complex, and involves moving lots of materials, making cuttings, and building embankments.