BigBoy had a centipede type tender, developed by the Union Pacific Railroad and used with all BigBoys. It had 14 wheels (4 leading and 10 trailing). The tender was 39' 1 3/4" long, 9' 7" high and 10' 10" wide. Fully loaded, it weighed in at 82 tons (164,000lbs). It had a capacity of 28 tons of semi-bituminous coal and 25,000 gallons of water.
Tender Coal Capacity: 28 ton (2000lbs/ton)
Tender Capacity: 25,000 gallons
In order to feed BigBoy's voracious appetite for coal, a large Stoker was used. This was like a cork screw, or auger, that pulled coal from the tender, broke it up, churned it through a large diameter pipe leading from the tender to the FireBox and shot it into the fire. A fireman could never shovel fast enough to feed the engine. BigBoy ate an average of 122,500lbs of water (12,500 gallons) and 22 tons (44,000lbs) of semi-bituminous coal per hour!