Railway Tilt

How soft soil tilts railway carrier ?
What it has to do with measurement ?

How do you measure soil movement accurately under the railway?
Well, I can be done and it is done. This video is about testing situation location Pernio Finland October 2009

First load sand to the carrier so much that soil can't last it.
Measure soil movement in may different point.
After the carriage is fallen down, look the data.
It is easy, this job took only two years to do,
but it was at start difficult to get mm accuracy height data without any reference.
I have made these measurement devices two times 100 pcs .

Pekka OH3GDO