3.1.1. Service life and maintenance frequency determination
In order to assess the long term economy, the service life of different components as well as policies for inspection,
preventive maintenance and renewal intervals are needed. For this purpose, life-cycle cost models have been developed
which often consider a standard unit of track with some given traffic load. The studies either aim at (a) conditionbased
maintenance, where focus is on inspection planning, or (b) prescribed / preventive maintenance, where focus is
on maintenance and renewal intervals.