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568 N. O. E. Olsson et al.with a wide range of train services and lines. As mentioned, this is a major differencecompared with road investments. As an alternative ex-post evaluation andcomparison between ex-ante and ex-post, all railways related investments in agiven part of the railway system could be evaluated as a whole with certainintervals, e.g. every 5 years.ConclusionsKey success criteria for travel time reductions from railway investments appear tobe the combination of infrastructure development and acceptance for timetableadjustments. Investments executed as integrated projects appear to be more likelyto achieve such acceptance for timetable adjustments compared with investmentsbuilt and decided upon section by section. A critical mass of potential improvementis needed to justify a timetable change that uses new infrastructure. Incontrast, sequenced decisions appear to provide a better cost control comparedwith integrated projects. Regarding the location of railway constructions, thisstudy particularly points to difficulties in realizing travel time reductions whenthere are single tracks on both sides of the new lines, and the train traffic alsopasses through an area with high-capacity utilization. In such a situation, extensionof double tracks seems to be more likely to realize expected travel timereductions.This study indicates a need to make it clear in the ex-ante project description offuture investment projects that the estimates for travel time, frequency, punctualityand number of travellers are dependent on appropriate timetable adjustments.Such a practice would give a higher accuracy of the project descriptions. To stateexplicitly the relation between timetable adjustments and the realization ofinvestment benefit can contribute to a tighter coordination between investmentand timetable planning.AcknowledgementsThe author thanks the Norwegian National Rail Administration and NSB AS forproviding access to staff and information related to the studied projects. Thevaluable comments of two anonymous referees are appreciated.ReferencesAspengren, N. C. (1999) Fra Roa til Bergen Historien om Bergensbanen (Oslo: Baneforlaget).Berg, P., Stene, E. A., Fon, A. M., Kvarsvik, T., Bye, B., Aksnes, L., Hallquist, Ø. and Pedersen, P. (1998)Gjennomgang av investeringer i samferdselssektorene, Rapport fra en arbeidsgruppe med deltakelse fraFinansdepartementet, Samferdselsdepartementet, Jernbaneverket, Vegdirektoratet og Luftfartsverket, Prosjektetfor styring av statlige investeringer (Oslo: Department of Finance).Bergendahl, G. (2002) Real optionsanalys för vägar och järnvägar—en tillämpning på projektet Citytunneln iMalmö. Available at: http://www.sika-institute.seBrennan, M. L. and Trigeorgis, L. (2000) Project Flexibility, Agency, and Competition: New Developments inthe Theory and Application of Real Options (New York, NY: Oxford University Press).Bruzelius, N., Jensen, A. and Sjöstedt, L. (1993) Svensk järnvägspolitik. En kritisk granskning (Stockholm:SNS).Flyvbjerg, B., Bruzelius, N. and Rothengatter, W. (2003) Megaprojects and Risk. An Anatomy of Ambition(Cambridge: Cambridge University Press).Flyvbjerg, B., Holm, M. K. S. and Buhl, S. L. (2004) What causes cost overrun in transport infrastructureprojects?, Transport Reviews, 24(1), pp. 3–18.