The Iron Rhine (Dutch: IJzeren Rijn / German: Eiserner Rhein) is a freight railway connecting the port of Antwerp in Belgium to Mönchengladbach in Germany by way of Neerpelt and the Dutch towns of Weert and Roermond.
The Treaty of London between the Netherlands and Belgium in 1839 recognised the independence of Belgium. As part of the treaty, Belgium had the right to build a road or canal from Sittard to the Prussian border over Dutch territory, with Belgium funding the construction. This right was further established in the Iron Rhine Treaty of 1873. At first Belgium planned to dig a canal, but in the end it opted for a railway.
In 1868 construction of the Iron Rhine started, and in 1879 the first trains used the railway. Initially, traffic was dense and frequent, but it decreased over time. Currently the western part of the railroad van be en is used by some trains between Antwerp and the Netherlands and Germany. Between Roermond and the German border, traffic has fully ceased since 1991.
In recent years Belgium has requested reopening of the Iron Rhine, based on the treaty of 1839, and the Iron Rhine Treaty of 1873. As part of the European policy of modal shift on the increasing traffic of goods, transport over railway lines and waterways is preferred over road transport.
However, the railroad runs through the nature reserve of De Meinweg, and nature activists fear destruction of the local habitat of several threatened species.

The issue was brought to the Permanent Court of Arbitration. In its ruling of May 24, 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 modernization 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.
This tunnel will cost more than 500 million Euros, so it is wise to look for alternatives.