Walker's brethren in the 572nd Transportation Company included Rodney Black of Roswell, New Mexico; Daniel Carrasco of Cucamonga, California; James R. Brobst of Newton Falls, Ohio; George F. Willhite; and Michael W. Werlinger.
The Company nicknamed themselves "The Gypsy Bandits" (dubbed so because the company was moved so often to wherever a tractor-trailer was needed and that they often robbed unauthorized Vietnamese vehicles) and their saying to each other was "Hamp."
Captained by Jim Donelan of Fort George Meade, Maryland, the Bandits served from the Vietnamese cities of Long Binh to Quang Tri. They sent numerous truck convoys to numerous cities. The primary cargo on these trucks was ammunition and rations, in support of units like the 1st infantry and 199th Light Brigade.
In April of 1969, the company was stationed at Long Binh, where they stayed until late January of 1971. During this time period, Walker perished while on a delivery route to Phuoc Toy, but his company still remained intact. Gathering over 98,000 loaded miles, the company supported operations operations north and west of Quang Tri in 1971. The strength of company was 178 men with 5 officers, divided into 3 truck platoons, a maintenance section, and a headquarters platoon. Time-efficient maintenance was a common problem in the operation of the 572nd.