linchpin wagon

noun, a wagon with wheels held on by linchpins | ‘linchpin’: a pin passed through the end of an axle to keep a wheel in position (COD)

“I don’t know if maybe you’ve ever seen them or not, linchpin wagons. Ah, they didn’t have nuts on the end of the wheel. They had like a Ford tractor for the three-point-hitch. Pins similar to that that went through the end of the axles to hold the wheel on.”