The proper maintenance of railways means the operations required to ensure that the railway's right-of-way, the structures, and the equipment, are serviceable. It also includes the repair work required to ensure that the structures and equipment, etc... are serviceable. When maintenance work is actually being carried out on the railway (on the right-of-way or on equipment), as a result of which the railway's standards are increased, then there is question of intensified maintenance. Maintenance level means a pre-defined quality, or objective level for the railway, structures, equipment etc... The maintenance of railways concerns both the substructure of the track and its permanent way. The substructure includes embankments, earth and rock cuttings, drainage, bridges, and culverts. The permanent way includes the track and its components, such as turnouts and ballast (Figure 1). The components of the track include the rails, sleepers, fastenings, and the rail joints.