The heaviest trains in the world are freight trains hauling bulk commodities such as coal and iron ore. One might distinguish between regular operations, and occasional record breaking runs. One might also distinguish between the total weight of the locomotives and its train of wagons, and the total payload.
- 1 Specifications
- 2 Countries
- 3 See also
- 4 References
- 5 External links
If the track and its alignment are strong, gauge is not so important. Among railways with over 20,000 t, the Sishen–Saldanha railway line use 1,067 mm (3 ft 6 in), while the others use 1,435 mm (4 ft 8 1⁄2 in).
The highest permitted weight per axle is:
- 1830 – Stephenson's Rocket 2.2 t
Another matter is the weight per metre or foot of train length. The strength of bridges is what mainly limits this. Examples:
- 12 tonnes/metre (Iron Ore Line, Sweden)
Curves must not be too sharp, otherwise wagons may be pulled off the track and derailed, especially with general freight trains where light and heavy wagons are intermixed. The meaning of "too sharp" depends as much on experience as on a specific formula.
The couplers must be strong enough in heavy trains. Janney couplers are used for the heaviest trains. The SA3 couplers handle trains of 6,000–8,000 tonnes, as Russian trains limited by loop lengths, etc.; maximum load of SA3 couplers have not been tested. The standard buffers and chain couplers used in Europe can only handle 3000–4000 tonnes train weight.
- Fortescue – 35,200 t gross train weight, 2,500 m long
- Xstrata 9,000 t (load) ?T (gross) 1,500 m long
- QR National (now Aurizon): 1,435 mm (4 ft 8 1⁄2 in) bulk iron ore train to Esperance, 11,000t (load); 14,500t (gross) 1,435 mm (4 ft 8 1⁄2 in) 32,320 t (gross weight excluding diesel locomotives) (40 t axleload)
- Specialised Container Transport/; 1,435 mm (4 ft 8 1⁄2 in) freighter from Parkes to Perth, June 2008, 6,000 t and 1,800 m with diesel locomotives / (crossing loops are 1,800 m)
- BHP Billiton: 1,435 mm (4 ft 8 1⁄2 in) June 2001 trial with 682 ore cars and eight distributed GE AC6000CW locomotives with a total weight of 99,734 tons.
- BHP Billiton 39,680 tonnes 
- Genesee & Wyoming Australia 1,435 mm (4 ft 8 1⁄2 in) bulk iron ore train to Whyalla - 82 wagons and 1,752 metres long, 12,254t
- Arrium 1,435 mm (4 ft 8 1⁄2 in) - 13,000 tonnes (4 locos, 160 wagons) - heaviest on national network.
- Bulk trains are limited to 3000 m length with up to 20,700 tonnes
- Iron ore trains on Quebec North Shore and Labrador Railway 33,000 tons
- Rotterdam-Dillingen iron ore trains - 6,000T
- Existing – 800 t – 1,000 mm (3 ft 3 3⁄8 in)
- Proposed – 4000 t – 1,435 mm (4 ft 8 1⁄2 in)
- Improvement due to heavier 60 kg/m rail, gentler curves and gradients.
- Mauritania Railway - 20,000 t – 1,435 mm (4 ft 8 1⁄2 in) – iron ore
Russia / Finland
- The longest and heaviest freight train ran as a test train on February 20, 1986, from Ekibastuz to the Urals was carried out with a coal train. The composition consisted of 439 wagons and several diesel locomotives distributed along the train. The mass of is 43,400 tonnes and the total length of 6.5 kilometres (4.0 mi).
- Chita - Zabaykalsk (break of gauge at Chinese border) up from 4,000 to 6,300 tonnes. Russia uses special SA3 couplers allowing higher weight than in most of Europe.
- In 2014 Russian Railways presented a new locomotive called 4ES5K adopted for 7,100 tonne trains to be put into operation in 2015.
- The heaviest trains in Finland weigh approximately 5,400 tonnes and carry iron ore pellets (taconite) from the mines and processing plant in Kostomuksha, Russia. They go from Kostomuksha to Oulu, Finland, as 60-car unit trains measuring approximately 880 metres (2,890 ft) in length. These trains are hauled by two Sr2 class electric locomotives at 25 kV AC. Due to the restrictions caused by passing loop lengths between Oulu and the port of Kokkola the trains are shortened to 30-40 cars in Oulu and are usually operated with Sr1 class electric locomotives for the rest of the way. The trains use exclusively Russian rolling stock and are equipped with SA3 couplers.
- Freight trains on the new North-South will carry 15,000 t and be 100 wagons long. Later estimates are for 15,000 t and 155 wagons.
Sierra Leone had a 762 mm (2 ft 6 in) narrow gauge railway with 5 t axleloads. Train loads were necessarily very limited, which increased costs counter-productively, as large numbers of small trains were needed to haul tonnages that heavier railways could haul with fewer trains. For example, in 1956 fourteen modern 4-8-2+2-8-4 Garratts were purchased from Beyer-Peacock. These locos increased the maximum load over 1:50 grades from 200 tons (203 tonnes) to 270 tons (274 tonnes).
- Sishen–Saldanha railway line: 41,400 t. (Gross weight) 3875 m long, 9 locomotives in 4 sets remote distributed power management (342 cars with 100t ore each)  Uses 3 ft 6 in (1,067 mm) and 50 kV AC.
- Manganese: 16,640 t 
Sweden / Norway
- On the Iron Ore Line which goes between Luleå, Sweden and Narvik, Norway, iron ore trains are hauled by 360 t IORE locomotives. These 8660 t trains (incl locomotive) are the heaviest in Europe. Special SA3 couplers, and 15 kV 16 2⁄3 Hz electrification are used. The iron trains go either Kiruna-Narvik or Gällivare-Luleå. Other very heavy trains go in flat areas but these trains go through a mountain range, although the uphill grades are at most 10 ‰ in the direction with loaded trains. Other heavy trains in Sweden are no more than 3500 t limited by buffers and chain couplers.
- 3250 t – electric hauled
- Many main routes in the western US allow cars with gross weights up to 315,000 lbs (142,882 kg).
- A Duluth, Missabe & Iron Range ore train pulled by a single 2-8-8-4 "Yellowstone" steam locomotive which totaled over 19,000 tons
- A BNSF train from Ogden, Utah, to Roseville, California, was 14,000 t
- A CN mixed freight train from Symington Yards in Winnipeg to Fond du Lac, Wisconsin, was over 22,500 tons
- Longest trains
- List of largest locomotives
- Minimum railway curve radius
- Extreme Trains
- Coupler (railway)
- Transport in Australia
- Transport in Brazil
- Transport in South Africa
- List of steepest gradients on adhesion railways
- High speed trains
- International Heavy Haul Association
- List of highest railways in the world
- William C. Vantuono (April 2002). "Control this! how distributed power helps railroads handle the world's longest, heaviest trains. demonstration union train – BHP Iron Ore Australia". Railway Age. findarticles.com. Retrieved 2008-11-16.
- "Hamersley Freight Line - Railway Technology".
- Trains magazine, February 2012 p38
- Railway Gazette International August 2009, p25
- Забайкальская железная дорога | Инвестиционный проект "Южный ход" | Общие сведения (Transbaikal Railway: The Southern Branch investment project: General information) (Russian)
- Railway Gazette International July 2011, p8.
- RailwaysAfrica September 2009, p14
- SA features prominently in history of rail transport
- Extreme Trains, Episode 1