This Master Thesis has focus on parts of the public transport system in Norway. The main topic in this thesis is:What variables must be calculated for the decision concerning the construction and implementation of the Norwegian High Speed Rail project, and how are the variables calculated?High Speed Rail does not have a single standard definition. High Speed Rail definition, given in the European Union definition, Directive 96/48 is suitable for many different systems of rolling stock, infrastructure and operating.1New lines shall be designed to guarantee safe uninterrupted travel at speed above 250 km/h on lines specially built for High Speed, while enable speeds of over 300 km/h to be reached in appropriate circumstances. Existing lines, which have been specially upgraded, shall be guaranteed a speed of 200 km/h. On other lines: Highest possible speed.2 Infrastructure of the Trans-European High Speed system shall be built especially for High Speed travel. Connecting lines may be included, in particular junctions of new lines, which is upgraded, for High Speed with stations located in town center, on which speeds must be adjusted to local conditions.3High Speed lines shall incorporate specially built lines prepared for speeds equal to or above 250 km/h and upgraded High Speed lines prepared for 200 km/h. Special features as a result of topographic, relief or town-planning constraints need to be adapted to each case on which the speed must change. High Speed train takes for granted that the characteristics of infrastructure and those of the rolling stock are compatible.4Challenges concerning costs and benefits, and budget deficit/surplus of the High Speed Rail projects in other countries (e.g. HS1 and HS2 in England, AVE in Spain, and High Speed Rail in California) will be empirical cases in this thesis, which all are influenced by political and technical challenges, which are relevant for the Norwegian High Speed Rail.1 International Union of Railways (2010) p. 12 International Union of Railways (2010) p. 13 International Union of Railways (2010) p. 14 International Union of Railways (2010) p. 1VIDuring the work with this specific topic, many elements have been taken account of but the demand uncertainty is probably the most critical and essential element of the Norwegian High Speed Rail project and is close related to a second variable; the passengers’ willingness to pay for high-speed rail.The topics for this master thesis is of theoretical character and has no ambition to quantify the level of financial needs for construction costs and operating costs of the High Speed Rail project.Producing a cost-benefit analysis (which is a list of quantified benefits and costs associated with the project, expressed in monetary values, calculated ex ante), with a valid conclusion turned out to be far out of reach for this thesis. The evolvement of the thesis has been a process with changing criteria for commenting selected High Speed Rail projects. An example is the decision (January 2012) to build the HS2 project in England.5Some empirical cases from High Speed Rail projects bring interesting challenges to the surface. Even when the number of passenger in other countries with High Speed Rail are many times the number of passengers between regions around Norwegian urban areas, High Speed Rail projects will very seldom pay off. There will not be any conclusion in this thesis about which scenario to choose.The number of passenger for each of the High Speed Rail projects in this thesis is too complicated to quantify. Aspirations for this thesis are therefore to focus on some of the challenges in these kinds of mega projects.The conclusion is that timing of the construction and implementing of the High Speed Rail project is crucial for the result of the cost benefit analysis whether the Norwegian High Speed Rail project should be built or not. Timing influences all the variables of the cost benefit analysis in this thesis. Timing is therefore crucial for the result of the analyses. It’s beyond the limit of this thesis to conclude whether the increasing demand for transport caused by population growth in the regions around cities in Norway should be solved by building the High Speed Rail project or not.It seems as the Norwegian High Speed Rail project is many decades too early for an efficient use of resources.