By 1940, oil-powered internal combustion engines started replacing coal-powered steam, increasing ranges, decreasing fuel-cargo requirements, and breaking the link between merchant marines and imperial-managed coal stations. Just as coal-fueled steam power trickled from the railways to the sea-lanes, now oil-powered internal combustion trickled back. Each advance helped make both transoceanic and inland transportation more regular and predictable. Costs plummeted, cargoes soared, reliability improved, and goods were moving on a scale hitherto undreamt of.
