SysTunnel is a complete system designed for monitoring tunnels, allowing the measurement of deformations, convergencies, and temperature in different sections of the structure, exclusively resorting to optical fibre sensors. This system was developed by EPOS in a partnership with the company FiberSensing and with Prof. Carlos Dinis da Gama from the Geotechnical Centre of Instituto Superior Técnico. In the Rossio Tunnel, 109 instrumentation sections have been installed, totalling 763 strain sensors and 109 temperature sensors. This measuring system installed in the technical niche inside the tunnel records the sensors data and performs the transmission management through the TCP/IP to the Server. This data is available and may be consulted afterwards in any PC, on REFER´s intranet through a Web interface.