The phenomena of packing and wear of ballast, under dynamic stresses lead to high maintenance frequencies and high maintenance costs. Several studies have shown that these settlements were linked to the high accelerations produced in the ballast by the passage of highspeed trains. Bituminous sublayers are used since the 1980s in several countries like the United States, Italy, Spain, especially on high-traffic and high-speed lines, to increase the stiffness of the track structure, and reduce these high acceleration levels. Recently in France, this technique attracted interest following the satisfactory behavior of the East European HSL. A high scale project with an asphalt concrete sublayer on the "Bretagne-Pays de la Loire" (BPL) high speed line, was launched. The innovative underlayment is intended, among other things, to reduce the amplitude of the accelerations produced at the passage of high-speed trains. HSL BPL has 105 km of innovative track with an asphalt concrete (GB) sublayer under the ballast, and 77 km with untreated granular (UGM) underlayment. In order to study the dynamic responses of these different structures and to understand the effect of the different layers on the dynamic response, four sections were instrumented (3 sections with an asphalt concrete track structure, and one with a standard granular structure) using, among others, accelerometers, strain gauges, temperature probes, etc. More than 100 sensors have been installed in the railway infrastructure at different positions and depths. Data acquisition has been performed during the speed up test phase , under controlled conditions; the same train crossing the line with speeds ranging from 160 to 352 km/h. Commercial traffic has been traveling on the BPL line since July 2017. In this paper, we will present the instrumentation as well as the acquisition system installed to collect all the measurements. Different results obtained during the speed up test phase are drawn, with a focus on comparisons of measurements between the different sections with UGM and GB layers.