After a series of failed negotiations, the Belgian and Dutch governments agreed to take the issue to the Permanent Court of Arbitration and respect its ruling in the case. In its ruling of 24 May 2005, the court acknowledged both the Belgian rights under the cessation treaty of 1839 and the Dutch concerns for the nature reserve. The 1839 treaty still applies, the court found, giving Belgium the right to use and modernize the Iron Rhine. However, it has to finance the modernisation of the line, while the Netherlands have to fund the repairs and maintenance of the route. Both countries will split the costs of the construction of a tunnel beneath the nature reserve.