Material Insights · Understanding the Material World

Coal transport: How it works

How 20,000-tonne trains and Capesize ships shift coal

What this tab covers How the energy actually moves, step by step: the science that makes it work and the engineering that makes it practical.

Coal is a heavy, low-value solid, so moving it is about tonnage. Unit trains, bulk carriers, barges, trucks and conveyor belts carry it from mine to port to power station or steelworks. A few pipelines once moved it as a slurry in water.

Step by step

  1. Load at the mineCoal is crushed, sometimes washed, and dropped from silos into wagons or trucks, or onto a conveyor.
  2. Haul by unit trainA unit train carries one cargo between two points. On China's Daqin line most trains carry 20,000 tonnes.
  3. Stockpile and shipAt ports, stackers build stockpiles and reclaimers feed shiploaders. Capesize and Panamax ships carry coal from Australia, Indonesia, Russia, South Africa and Colombia, mainly to Asia.
  4. Barges, trucks and conveyorsBarges and trucks serve riverside or nearby plants; enclosed pipe conveyors cover a few to a few tens of kilometres.
  5. Slurry pipelines (rare)Ground coal mixed with roughly its own weight of water was pumped up to 439 km, then dewatered at the power station.

The science

Moving a tonne takes energy to overcome rolling resistance (rail), water drag (ships, barges) or rolling plus air drag (trucks). Steel wheels on steel rails deform very little, so one locomotive can pull thousands of tonnes. Ships are cheaper still per tonne-km because drag per tonne falls as hulls grow. In a slurry, turbulence keeps fine particles suspended, but the coal must be dried afterwards.

The engineering

Heavy-haul railways use strong track, high axle loads and locomotives spread through the train under radio control so long trains stay together on curves. Wagons have bottom doors or are tipped by rotary dumpers. Ports use rail loops, stacker-reclaimers and shiploaders; bulk carriers load in a set sequence so the hull is not overstressed. Pipe conveyors roll the belt into a dust-tight tube.

Key numbers

World coal trade (2025) about 1.48 billion tonnes, down about 4% from the 2024 record1 Daqin heavy-haul line, China 653 km; 390 million tonnes in 20255 Daqin heavy-haul trains about 82 a day, about 51 of them 20,000-tonne trains (2025 average)6 Share of US power-sector coal moved by rail 69% (2019)4 Capesize and Panamax standard sizes about 182,000 and 82,000 deadweight tonnes22 Black Mesa slurry pipeline (closed 2005) 273 miles (439 km), 18 inches, about 4.8 million short tons a year1220

Sources

  1. Coal Mid-Year Update 2026: Trade IEA, 2026
  2. Rail continues to dominate coal shipments to the power sector (2019 data) US EIA, Today in Energy, 2020
  3. Chinese heavy haul coal traffic plateaus International Railway Journal, 2026
  4. Daqin Railway 2025 net profit down nearly 35%, targets 400 Mt for core line SXCoal, 2026
  5. Black Mesa Coal Mine and Pipeline, Arizona Center for Land Use Interpretation, 2024
  6. Environmental Impact Statement notice: Black Mesa Project, Arizona (Office of Surface Mining) US Federal Register, 2004
  7. Shipping market information (standard bulk carrier sizes) NYK Line, 2026