Classic Machines TractorsClassic Machines: The Allis-Chalmers HD-19 revisitedContrafed PUblishingJune 27, 2018December 10, 2019 by Contrafed PUblishingJune 27, 2018December 10, 2019 Allis-Chalmers led the charge for a bigger, higher horsepower track type tractor following World War Two. The resulting model HD-19 was a breakthrough in many...