After optical measurement runs have been read into the database and edited, rail inventory can be calculated. If runs are joined, split, recalculated for a different rail type or rail classification criteria, or otherwise substantially edited after inventory has been calculated, you must recalculate inventory for those runs in order to capture the updates.
The inventory calculation summarizes the rail in a given section of track by rail type (weight) and wear classification. The results of the calculation are written to the database, and used in the Rail Inventory Report and other reports.
The inventory calculation goes through all profiles in a given data collection run. Looking at each side separately, it divides the rail into sections of the same rail weight. Each section is further subdivided into lengths of the same rail classification. The minimum rail section length for inventory purposes is user-defined. Each segment of minimum length is classified according to the worst (i.e. highest-wear) rail classification of any profile within the segment. This reflects the idea that there is a minimum length of rail that makes economic sense to replace.