decapod
A nickname for either the 0-10-0 or 2-10-0 train configurations.
decapod: the ten-wheeled freight locomotive that owned the rails
A decapod is a steam locomotive with ten driving wheels, arranged as either 0-10-0 or 2-10-0 in Whyte notation. The term comes from the Greek deca (ten) and pod (foot), though railroad workers simply called them ten-drivers. These machines appeared in the early 1900s as railroads demanded heavier freight trains and steeper grades than smaller engines could handle.
The 2-10-0 decapod, with two leading pony wheels and ten driving wheels, became the standard variant in North America. The extra length and weight gave it immense tractive effort, often exceeding 60,000 pounds. The 0-10-0 configuration, without leading wheels, was less common and appeared mainly in industrial settings where tighter curves were possible. Both types required substantial water and coal capacity, so they were typically paired with large tenders.
Decapods excelled at low-speed, high-tonnage work: dragging ore cars from mines, hauling through mountain passes, and moving heavy freight in rail yards. Their ten driving wheels distributed load across the rail better than smaller engines, reducing track damage and allowing operation on worn or light rail. They were not fast machines. A decapod might sustain 25-35 mph under load where a lighter ten-wheeler would manage 45 mph.
The wear and limitations
The major drawback was flexibility. With ten wheels all fixed to the frame, a decapod could not navigate tight curves. Radii below 300 feet became problematic, which restricted their use on branch lines and industrial sidings where older tank engines operated freely. Wheel slip was another challenge: the enormous adhesive weight made them prone to spinning the driving wheels on wet or greasy rail, especially during hard starting.
Decapods remained in heavy freight and switching service into the 1950s, particularly on coal roads and western mountain lines. Their mechanical simplicity and proven design made them easier to maintain than compound or articulated locomotives, though the sheer number of journals and moving parts still demanded constant attention. By the diesel era, most had been scrapped, though a handful survive on heritage railways.