Rail is of foremost importance to support long distance trade corridors and has experienced a resurgence in the recent years, particularly in North America. It accounts for close to 40% of all the ton-km transported in the United States, while in Europe this share is only 8%. Still, rail freight corridors have a functional typology which can be differentiated by the distance (scale) they service. Rail corridors fit within a specific freight distribution strategy but are embedded to one-another:
- Short distance. Conventional transport economics underlines that rail is not a very suitable mode for short distances. Short distance rails corridors are thus established under very specific circumstances, namely where there is acute congestion and a modal shift to rail is required to improve the capacity and throughput of a gateway or hub. This often concerns on-dock rail facilities where containers are exiting / entering a port terminal on rail instead of on truck, but the destination of these rail shipments often goes much further inland. The Alameda corridor is an example of a short distance rail corridor of 20 miles (32 km) aiming at expanding the throughout of the San Pedro port cluster by shifting away containerized traffic from trucks. The Panama Canal Railway is a dedicated corridor for maritime shipping lines to shuffle containers to and from the Atlantic to the Pacific side of the canal.
- Hinterland access. The rail corridor is a strategy to expand the market area of a gateway, often linking on-dock rail facilities to an inland terminal facility where containers are moved to trucks to their final destination. It is particularly suitable with dense hinterlands such as along the Rhine/Scheldt delta. Over a longer distance, a network of inland ports can emerge.
- Landbridge. A landbridge is a long distance continental rail corridor linking gateways which ensures the continuity of global supply chains. The North American landbridge is mainly the outcome of growing transpacific trade and has undergone the containerized revolution; container traffic represented approximately 80% of all rail intermodal moves. Landbridges are particularly the outcome of cooperation between rail operators wishing to capture long distance traffic and shippers wishing to reduce shipping time and costs, as well as having additional options to route cargo.
- Circum-hemispheric. Such systems of circulation go beyond rail corridors to integrate a sequence of maritime and land transportation corridors in a seamless fashion. A circular transport chain across a hemisphere is thus established. Such corridors are emerging, with the Northern East-West Corridor initiative (spearheaded by the International Union of Railways), connecting the Atlantic with the Pacific through the transsiberian has been in the design phase for decades. The “Belt and Road” initiative (spearheaded by the Chinese government) has a similar objective, but mostly focused in Central and South Asia. In addition to rail corridors, it also includes a maritime transportation component (dubbed the maritime silk road) connecting China, Southeast Asia, South Asia and Eastern Africa.