Tampere University of Technology and the Finnish Transport Agency conducted a full scale stability test on an old railway embankment in October 2009. Though the subsoil consisted of very soft and sensitive clay, the diverse instrumentation gave a lot of valuable information about the capacity and performance of different instrumentation equipments in general. Measurements included pore water and earth pressure gauges, automatic inclinometers, different displacement measurements and laser scanners. The measurement frequency varied from 1 s to 2 min depending on needs and the equipment. A selection of measured data was also plotted to visual curves in real-time. The instrumentation was extensive, containing about 300 separate points with various instruments. Loading was increased in less than 36 hours from 0 kPa to 87 kPa (218 kN/m), with failure occurring two hours after the loading ended. Deformations and pore pressures began to increase exponentially after the loading had ended due to time dependent behavior and strain-softening of the clay. In hard soils the development of displacements can be even more fragile and unexpected. Even though all the monitoring instruments responded accurately, some differences between instruments were recognized. Therefore the test gave valuable information considering the importance of measuring intervals, correct assumptions of limiting values of measuring variables and information regarding the effective placement of the instruments. These issues are in key position when monitoring is used to reduce geotechnical safety risks.