In this paper we estimate the impact of line capacity utilisation on the marginal cost of rail infrastructure renewals. Previous studies are mainly concerned with deterioration costs caused by traffic. This paper contributes to the literature, showing that increased line capacity utilisation can – in addition to higher deterioration costs – generate increased costs for carrying out a renewal project and/or more frequent renewals, where the latter can be motivated by efforts to curb expected delays. A top-down econometric approach is used on a Swedish dataset comprising information on renewal costs for track, electric installations, signalling, telecommunication, and other installations such as barriers, fencing and lubrication equipment. The results are relevant for rail infrastructure managers, especially in Europe where directives by the EU stipulate that track access charges are to be based on direct costs in order to contribute to an efficient use of the infrastructure.