The paper is concentrated on solving a mixed decision problem of mass transit line construction and vehicles’ depots location (MTLC&VDL). The authors have iteratively solved this problem as a function of scenariobased, long-term travel demand changes, and finally have analysed the generated results. As a product of the computations, it has been proved that the solution of the mixed MTLC&VDL decision problem depends on changes in travel demand, both in terms of the line construction and the location of the depot. 5 and 10% increase of travel demand leads to changes in the optimal mass transit line’s configuration, while the change of the optimal depot location takes place with 10% of the travel demand change. The results have implied a conclusion that to make strategic decisions on transport systems and solving mixed decision problems, forecasting travel demand changes (its volume and structure) over the long-term horizon has to be performed.