The estimated elasticities can be used to derive
estimates of marginal costs for each single track unit, i.e.
of the wear and tear inflicted on tracks by allowing for an
additional train of some certain weight to pass over a track
unit. To this end, we must start by including a distance
component in the traffic activity measure. While elasticity
is measured relative to an increase in gross ton per track
unit, the preferred marginal cost measure is due to an increase in Gtkm. The measure of marginal cost (Mc) per
Gtkm is then