  This document is the third sub-report from the research project SATT
(Samplanering av trafikp{\aa}verkande {\aa}tg\"arder och trafikfl\"oden,
modellstudie / Coordinated planning of temporary capacity restrictions and
traffic flows, model study). The report summarizes the modelling alternatives
that have been considered. The main result of the model study is that we
propose a bi-level approach for handling the two parts of the problem, i.e. the
scheduling of renewal projects and the subsequent adjustments of railway
traffic flow. The contributions are: (1) a mixed integer formulation for
scheduling project tasks, and (2) a network flow formulation for establishing
the possible volumes of railway traffic during the imposed capacity
restrictions of these project tasks. The intended usage of the model is for
economical planning of a specific production year, which takes place before the
timetabling process starts. This document introduces the problem and gives a
full description of (1) along with results from computational experiments that
have been conducted with this model. An accompanying report gives the details
of the final formulation of (2).
