. Railroads are subject to the
network effect: the more points they connect to, the greater the value of the system as a whole. Early railroads were built to bring resources, such as coal, ores, and agricultural products, from inland locations to ports for export. In many parts of the world, particularly in the Southern Hemisphere, that remains the primary use of freight railroads. Greater connectivity opens the rail network to other freight uses, including non-export traffic. Rail network connectivity is limited by many factors, including geographical barriers such as oceans and mountains, technical incompatibilities, particularly differences in
track gauges and
railway couplers, and political conflicts.
The largest rail networks are located in North America and Eurasia. Long-distance freight trains are generally longer than passenger trains, with greater length improving efficiency. Maximum length varies widely by system. (
See longest trains for train lengths in different countries.) Many countries are moving to increase the speed and volume of rail freight to win markets, relieve overburdened roads, and speed up shipping in the age of
online shopping. In Japan, trends towards adding rail freight shipping are more due to the availability of workers rather than other concerns. Rail freight tonnage as a percent of total moved by country: • Russia: about 12% in 2016 up 11% • Japan: 5% in 2017 Rail freight ton-milage as a percent of total moved by country: • USA: 27.4% in 2020 • China: 15.9% in 2022 •
EU28: more than 20% of all "inland traffic" in 2021
Eurasia –
Jiamusi Railway in
Yichun,
Heilongjiang There are four major interconnecting rail networks across the Eurasian landmass, along with other smaller national networks. Most countries in the European Union participate in an auto-gauge network. The
United Kingdom is linked to this network via the
Channel Tunnel. The
Marmaray project connects Europe with eastern Turkey, Iran, and the Middle East via a rail tunnel under the
Bosphorus. The 57-km
Gotthard Base Tunnel improved north–south rail connections when it opened in 2016. Spain and Portugal are mostly broad-gauge, though Spain has built some standard-gauge lines that connect to the European high-speed passenger network. A variety of electrification and signaling systems is in use, though this is less of an issue for freight; however, clearances prevent double-stack service on most lines.
Buffer-and-screw couplings are generally used between freight vehicles, although there are plans to develop an automatic coupler compatible with the Russian SA3.
See Railway coupling conversion. The countries of the former
Soviet Union, along with
Finland and
Mongolia, participate in a
Russian gauge-compatible network, using
SA3 couplers. Major lines are electrified. Russia's
Trans-Siberian Railroad connects Europe and Asia, but lacks the clearances required to carry double-stack containers. Numerous connections are available between Russian-gauge countries and their standard-gauge neighbors in the west (throughout Europe) and in the south (to China, North Korea, and Iran via Turkmenistan). While the USSR had important railway connections to Turkey (from Armenia) and to Iran (from Azerbaijan's
Nakhchivan enclave), these have been out of service since the early 1990s, since several
frozen conflicts in the Caucasus region have forced the closing of the rail connections between Russia and Georgia via Abkhazia,
between Armenia and Azerbaijan, and
between Armenia and Turkey.
China has an extensive standard-gauge network. Its freight trains use
Janney couplers. China's railways connect with the standard-gauge network of
North Korea in the east, with the Russian-gauge network of Russia, Mongolia, and Kazakhstan in the north, and with the meter-gauge network of Vietnam in the south.
India and
Pakistan operate entirely on
broad gauge networks.
Indo-Pakistani wars and conflicts currently restricts rail traffic between the two countries to two passenger lines. There are also links from India to Bangladesh and Nepal, and from Pakistan to Iran, where a new, but little-used, connection to the standard-gauge network is available at
Zahedan. The four major Eurasian networks connect to neighboring countries and to one another at several
break of gauge points. Containerization has facilitated greater movement between networks, including a
Eurasian Land Bridge.
North America Canada,
Mexico and
the United States are connected by an extensive, unified
standard gauge rail network. The one notable exception is the isolated
Alaska Railroad, which is connected to the main network by
rail barge. Due primarily to external factors, including geography and a commodity mix that favors coal, the modal share of freight rail in North America is one of the highest worldwide. Rail freight is well standardized in North America, with
Janney couplers and compatible
air brakes. The main variations are in
loading gauge and maximum car weight. Most trackage is owned by private companies that also operate freight trains on those tracks. Since the
Staggers Rail Act of 1980, the freight rail industry in the U.S. has been largely deregulated. Freight cars are routinely
interchanged between carriers, as needed, and are identified by company
reporting marks and serial numbers. Most have computer-readable
automatic equipment identification transponders. With
isolated exceptions, freight trains in North America are hauled by
diesel locomotives, even on the electrified
Northeast Corridor. Ongoing freight-oriented development includes
upgrading more lines to carry heavier and taller loads, particularly for
double-stack service, and building more efficient intermodal terminals and
transload facilities for bulk cargo. Many railroads interchange in Chicago, and
several improvements are underway or proposed to eliminate bottlenecks there. The U.S.
Rail Safety Improvement Act of 2008 mandates eventual conversion to
Positive Train Control signaling. In the 2010s, most North American Class I railroads have adopted some form of
precision railroading.
Central America The
Guatemala railroad is currently inactive, preventing rail shipment south of Mexico.
Panama has freight rail service, recently converted to standard gauge, that parallels the
Panama Canal. A few other
rail systems in Central America are still in operation, but most have closed. There has never been a rail line through Central America to South America.
South America Brazil has a large rail network, mostly meter-gauge, with some broad-gauge lines. It runs some of the heaviest iron ore trains in the world on its metre-gauge network.
Argentina has Indian-gauge networks in the south, standard-gauge networks in the east, and meter-gauge networks in the north. The meter-gauge networks are connected at one point, but there has never been a broad-gauge connection. (A metre-gauge connection between the two broad gauge networks, the
Transandine Railway was constructed but is not currently in service.
See also Trans-Andean railways.) Most other countries have few rail systems. The standard gauge in the east connects with Paraguay and Uruguay.
Africa The railways in Africa were mostly built by colonial powers to bring inland resources to ports. There was little regard for eventual interconnection. As a result, there are a variety of gauge and coupler standards in use. A gauge network with Janney couplers serves southern Africa. East Africa uses
metre-gauge. North Africa uses
standard gauge, but a potential connection to the European standard gauge network is blocked by the
Arab–Israeli conflict.
Australia intermodal service from
Perth in Western Australia Rail developed independently in different parts of Australia and, as a result, three major rail gauges are in use. A standard gauge
Trans-Australian Railway spans the continent. ==Statistics==