I often get asked, “What is it that you do?” when I tell people I’m out in the middle of nowhere doing a recon.
The stability of the the railway is dependent on the rocks and dirt underneath the steel and sleepers. There are three layers to the rail, a stabiliser mix (basically rocks with a bit of concrete), a capping layer, then the ballast. The ballast is usually 40-70mm rocks that are shaped perfectly to fit together when weight is applied to it. The more weight, the tighter it grips to itself.
Occasionally parts of the rail line get filled with mud and water and that causes the whole section to sink and slide about which makes the track bumpy and dangerous. When that happens, it is time for a track recon.