Privileged transit traffic or corridor traffic is traffic of one country across the territory of another country without usual customs and passport checks. The corresponding line of communication (usually a railway) is called the (privileged) traffic corridor and a train used in this kind of transit is called a corridor train (, ). The reason for such arrangements is usually border changes or border creation which cut through an existing transport corridor.
Examples
Examples are listed with headlines for the country enjoying the transit privilege, not the country offering it.
Belgium
Vennbahn was a railway built 1885 at the time fully in Germany. In 1919 some areas were transferred to Belgium. The railway did as a result cross the new border several times. To handle this, the railway embankment with tracks were also made Belgian territory if inside Germany, without having border controls at the road-rail crossings. The railway was dismantled in 2008, although the embankment still belongs to Belgium. As a result six German exclaves surrounded by Belgian territory were created as well as one counter-enclave. Five enclaves remain today. The sixth enclave and the sole counter-enclave no longer exist.
Estonia
The road from Värska to Ulitina in Estonia, the only road to the Ulitina area, goes through Russian territory for one kilometre (0.6 mi) of its length, an area called Saatse Boot. This road has no border control, but there is no connection to any other road in Russia. It is not permitted to stop or walk along the road. This area is a part of Russia but is also a de facto part of the Schengen area. This arrangement started in 1991 and remains to the present.
Finland
Finland leases the -long Russian part of the Saimaa Canal from Russia and is granted extraterritoriality rights. Russian visas are not required just to pass through the canal, but a passport is needed, and it is checked at the border.
Norway
The small road between Sandvika and Tunnsjø senter in Trøndelag county in Norway goes through Sweden for 7 km. It is called road Z821 in Sweden and (nowadays) road 7012 in Norway on both sides of the border. It had the privilege of right-hand traffic also before 1967 when the rest of Sweden had left-hand traffic. Customs control are only occasional like many small roads over the border.
Poland
A 1931 agreement between Poland and Romania for railway traffic between parts of Poland across Romania, between Zaleszczyki and Jasienów Polny (now Yaseniv-Pil'nyi). Since 1945, both places have been in Ukraine. During the years between the world wars German trains could travel to and from East Prussia across the Polish Corridor with legally sealed doors, thereby relieving the passengers of the need to obtain Polish visas.
Russia and Kazakhstan
In former Soviet Union, railways were built before the internal borders were made at present places, or not regarding them. Trains might go a stretch into another country and back. Some examples are: Railway connection between mainland Russia and its Kaliningrad Oblast exclave across Belarus and Lithuania (through Vilnius railway station). This was not privileged between 2007 and 2020 since normal passport and visa rules apply (since Lithuania entered the Schengen area in 2007).
Since the outbreak of the COVID-19 pandemic in 2020, the train has become privileged transit traffic again due to border closure by Lithuania, and now trains run non-stop through the territory of Lithuania. After the Russian invasion of Ukraine 2022, this traffic and any border crossing trains between Lithuania and Russia or Belarus are not going. Near Taraz, Kazakhstan, the railway Aktobe–Almaty passes briefly into Kyrgyzstan. Between Oral and Aktobe, Kazakhstan, the railway goes through Russia for over 100 km. Between Saratov and Astrakhan, Russia, the railway goes briefly through Kazakhstan twice. A branch of the Trans-Siberian Railway between Chelyabinsk and Omsk, Russia passes through the city Petropavl, Kazakhstan