Since the population growth of Stockholm Region is rapid, leading to larger demand on Public Transport and especially metro, four Municipalities of the Region have agreed on the expansion of the metro network. Blue metro line will be extended to Nacka and Hagsatra in the south and Barkarby in the north of the Swedish capital. The new railway line connections have been already planned, while the operation of the expanded line is analyzed in the current thesis. Taking the expected increase of passenger volumes and the operation of the current Blue line into account and following the safety restrictions, two alternative regular timetables of the expanded Blue line, limited to the morning rush service on a working weekday, have been constructed. The operation at stations of low expected passenger volume on the train is evaluated concerning the satisfaction of the operator. The rst alternative metro operation with trac every 4 minutes during the rush hour is concluded to be less ecient than the second alternative with 5 minutes headway, as 21 % larger amount of rolling stock is needed and more seats are not occupied. Finally, in order to achieve higher operational eciency at the low-demanded stations, a third Blue line operation, that is based on the second alternative and it includes short services, operating on a part of the line and not on the full-length of it, has been proposed. Although the number of trains needed for the morning peak hour operation remains constant between the second and third alternative operations, the proportion of empty seats at the analyzed stations is expected to be lower during the last alternative operation, resulting in a metro line scheduling that satises the operator most.