The pap er is organiz ed as follows . In Sec tions 2-5, we discuss the global
planning problems o c curring at the s trategic, tactical, op erational and short
term planning level. The lo cal planning proble ms are disc ussed in Sec tion 6.
Although the fo cus of the pap e r is on planning problems, OR models can
also be used during operations. This topic is discussed briefly in Section 7.
Finally, we conclude the paper in Section 8 with some final remarks.
2 Strategic planning
Rolling stock and crew are the main resources of a railway operator. At a
strategic level decisions need to be taken about the amount of rolling stock
units and the number of crews which are necessary for the coming years.
Notice that the planning horizon for rolling stock is different (longer) than
for crew. Another important issue at the strategic level is the product that
will be offered to the passengers. Therefore, main decisions about the line
structure need to be taken at this level. Although the detailed decisions are
normally taken at the tactical level, we decided to discuss this topic in this
section about strategic planning.