The encyclopedia · Engineering & Operations · Technical decision · 1979–1984

APL's 1984 StackTrain doubled container capacity per railcar

After pioneering dedicated intermodal trains in 1979, APL redesigned rail wagons to stack containers two high — StackTrain, 1984, halving rail cost per box.

American President Lines (APL)

the move

APL pioneered coordinated ship-and-train schedules in 1979, linking U.S. ports with inland cities. But each railcar carried only one container, so long intermodal hauls stayed expensive per box.

In 1984 APL and the railroads introduced double-stack railcars — well cars with a lowered middle that carried one container between the wheels and another on top. The first all-double-stack trains ran coast to coast that year under the StackTrain brand.

Doubling payload per car cut rail cost per container dramatically and made intermodal competitive with long-haul trucking; double-stack trains went on to become standard across North America and later in India, China and Australia.

The move combined engineering (the well-car) with network design (dedicated trains matching ship schedules) — the container era's rail half of the story.

why it works

Stacking doubled payload without adding train length or crew.
The lowered centre of gravity kept taller trains stable.
Fewer cars per container cut fuel and track cost per box.
It made rail the cheap long-haul leg of container supply chains.

the payoffUse the free vertical space: stack containers two highclever

what transfers

Look for the dimension nobody is using: the vertical space above a railcar was free, and using it halved the cost of moving a box by rail.

what came after

After NOL bought APL in 1997 it sold the stack-train business in 1999, but double-stack rail became the global standard; APL later exported the concept to India, launching a container train service there in 2007.

references

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