GR translation: down the engineered scars of Swiss avenues

[Mike Jing]

V264.4-7, P267.27-30   “Pero ché, no sós argentino. . . .” A long look
away, down the engineered scars of Swiss avenues, looking for the South he
left. Not the same Argentine, Slothrop, that that Bob Eberle’s seen toasts
to Tangerine raised in ev-ry bar across, now. . . .

What are "the engineered scars of Swiss avenues" exactly? Are the avenues
themselves the scars, or is it something else?