Levels of maintenance

Maintenance may be divided in 5 levels: • The first level includes the actions of checking (including technical inspections) and monitoring undertaken before the departure (pre-departure) or on route. This level is regulated in TSI OPE and is not on the responsibility of ECMs. • The second level includes inspections, checks, tests, fast exchanges of replaceable units and preventative and corrective operations of limited duration between two scheduled journeys. • The third level corresponds to the operations carried out mainly in specialised facilities of a maintenance centre. It includes interventions of preventative and corrective maintenance and scheduled exchanges of components. The vehicle is not in active service during this level of maintenance. • The fourth level comprises the major maintenance operations, generally called overhauls (of modular subsystems or of the complete vehicle). • The fifth level comprises the refurbishment, modifications, very heavy repairs, renewal or upgrading, except where they are the subject to new authorisation under the interoperability Directives. The levels of maintenance are usually combined and grouped as following: • Light maintenance Also called line maintenance. Represents all measures carried out on the complete vehicle subsystem and replacement works (including related measurements and testing). Light maintenance may include level 2 and level 3. • Heavy maintenance Also called base maintenance (including renovation). Represents all measures, undertaken to establish the actual condition and/or to reinstate the nominal condition, that necessitate partially or completely disassembling of the vehicle (including related measurements and the associated measuring and testing). It represents also all measures to recondition components or spare parts. Heavy maintenance may include level 4 and level 5.