Regional differences in rail freight transport systems
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 the southern hemisphere, that is still the main use of freight railroads. Greater connectivity opens the rail network to other freight uses including non-export traffic. Rail network connectivity is limited by a number of factors, including geographical barriers, such as oceans and mountains, technical incompatibilities, particularly different 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.
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.
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 shipping supplies. Many railroads interchange in Chicago, and a number of 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.
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, but a connection, FERISTSA, from Mexico to Panama, has been proposed in the past.
There are four major interconnecting rail networks on the Eurasian land mass, along with other smaller national networks.
•Most countries in the European Union participate in a standard 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 will improve north-south rail connections when it opens in 2016. Spain and Portugal are mostly broad gauge, though Spain has built some standard gauge lines that connect with the European high speed passenger network. A variety of electrification and signaling systems are in use, though this is less of an issue for freight, however overhead electrification prevents double stack service on most lines. Archaic buffer and chain couplers are generally used for freight, though 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 with Asia, but does not have the clearances needed to carry double-stack containers.
•China has an extensive standard gauge network. Its freight trains use Janney couplers.
•India and Pakistan operate extensive broad gauge networks. India also has substantial metre gauge trackage, but it has a Project Unigauge to convert much to broad gauge. Indo-Pakistani wars and conflicts currently restrict rail traffic between the two countries to two passenger lines. There are also links to Bangladesh and Nepal. Broad gauge enables Indian Railways to operate double stack service without the use of the special well cars needed elsewhere.