Page 261 - 360.revista de Alta Velocidad - Nº 5

Maintenance. From asset management to direct cost calculation.
A key issue for the future of the HS Railways System.

that can be extrapolated. The analyses to separate the sections by homogeneous
types must consider the following parameters: type of infrastructure, type of track
weaponry, climatology, layout in plan and elevation, etc.

These data would be cross-matched with data of traffic to obtain an estimation of costs
by train and characteristics of the same in each specific section, producing a system of
equations with as many equations as sections, and as many unknowns as types of trains,
and characteristics of traffic. This would be easier in High Speed tracks, as the rolling
stock would be more homogeneous.

From our point of view, this method would present the following advantages:

1. Starting from actual damage to the track, not from simulations, whose results
would need to be calibrated.

2. With many track sections, a good amount of different cases would be available.

3. For different levels of track quality, the accumulated damages can be assessed,
making possible to extrapolate in other cases with a different initial quality of the
track.

4. It would be possible to calculate the real cost per type of train for each section of
track.

5. This methodology, consisting of integrating the cost model with the asset
management model, has the challenge of gathering data from both the financial
department and the asset management department.

6. Conclusions

The integration of European Directives leads infrastructure managers to the use of the
methodology of direct costs for the assessment of charges. One of the main costs incurred
by railway infrastructure managers is maintenance and part of it is directly attributable
to railway operation. Therefore, it must be reflected in the calculation of the tariffs.
However, the cost of maintenance resulting from the passage of a train is not easily
assessed. Therefore, different approaches have been developed, such as the econometric
one, where a generalized cost function is determined to obtain the marginal cost, or the
engineering approach, based on dynamic simulations, in which a correspondence is made
between the behaviour of the trains and the damages produced on the track.
It should be noted that the methodology of direct costs has several limitations:

• Tracks with lesser quality, and thus, with grater maintenance needs, will have
higher marginal costs. However, the major maintenance needs may be due to non-
trafficdependent factors:

• By the presence of worse layouts, with more curves and steeper slopes.
• Greater deterioration of elements. The higher the wear, the higher the wear
rate, and the higher maintenance requirements. Tracks in worse state are
likely to cause greater damage to trains, due to the presence of defects which

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