Vennbahn

It is now entirely in Belgium, because the trackbed of the line, as well as the stations and other installations, were made provisional Belgian territory in 1919 (permanent in 1922) under an article of the Treaty of Versailles.

The treaty (not the location of the trackbed, per se) also created one small Belgian counter-enclave, a traffic island inside a three-way German road intersection near Fringshaus [de] which lasted until 1949.

[3] After the First World War due to the Treaty of Versailles, the German Reich had to cede districts of Eupen and Malmedy to Belgium on 10 January 1920.

On 27 March 1920, a border demarcation commission, which included representatives from France, the United Kingdom, Italy and Japan, determined that the Belgian state should be the owner of the railway line and its stations.

[7] It was reported in 2008 that, with the Vennbahn no longer operational, Belgium might have to return the land the line runs along to Germany, which would result in the reunification of the exclaves with German territory.