On the 19th of February 2010, the Ministry of Transport and Communication presented the Norwegian National Rail Administration with the task of assessing different aspects of the future of high-speed rail in Norway. The report, the Norwegian High-Speed Rail Assessment (NHSRA), consist three separate evaluations where the climate assessment by Bergsdal et al. (2012), motivated this thesis. Results from the report identify the railway infrastructure as the dominant emission source for the corridor, with the length of tunnels representing the determining factor. Simultaneously, an ongoing debate is comparing the safety and performance of track and tunnel technologies traditionally used in Norway to that of foreign tunnelling technology such as the drill and blast method which apply a full cast (European method), and a double shielded tunnel boring machine (TBM). The newest development in track technology is the slab track, which is now evaluated for tunnels and bridges in Norway (Jernbaneverket 2011). This thesis contributes to the ongoing debate concerning the construction of infrastructure for high-speed rail in Norway, by emphasizing the environmental impact of several relevant technologies and geological conditions. The assessment includes an evaluation of the impact of different tunnelling and track technologies, calculated for operation speeds of both 250km/h and 330km/h. Further, the environmental impact of different levels of support work and grout is assessed. In addition, this thesis includes a sensitivity analysis of the impact of service life for railway components. The assessment is calculated for two functional units: one meter tunnel and tunnel track, and for the case corridor, the potential high-speed rail corridor between Oslo-Stavanger, estimated for 250km/h obtained from the NHSRA by Bergsdal et al. (2012).Our results from this assessment account for the use of cement, steel and copper as the environmentally most important materials. Among the railway components, the tunnel lining and grout constitute the highest emission level of the case corridor. The different technical alternatives are compared against the technologies traditionally applied in Norway, and an average level of support work, which represents the baseline results of this thesis. Our results indicate that the double shielded tunnel-boring machine is the technology that contributes to the highest increase of emission level compared to baseline. Further, the variables that hold the greatest potential of reducing total emission level is the installation of slab track in tunnels and bridges, and level of grout in the tunnel construction.