The Cambridge History of India, Vol. I: Ancient India v1.c15.132

v1.c15.132

From Sukkur a branch railway traverses the desert northwestward to the foot of the hills below the Bolān pass. This part of the desert occupies a re-entering angle of lowland, with the mountains of Afghānistān to the north and those of Baluchistān to the west. On the map, the Afghān ranges have the effect of being festooned from the Bolān eastward and northward. The railway ascends to Quetta either by the Mushkāf valley—the actual line of the Bolān torrent having been abandoned—or by a longer loop line, the Harnai, which runs to the Pishīn valley, north of Quetta. The latter is the usual way. By the Mushkāf route the line is carried over a boulder-strewn plain about half a mile broad in the bottom of a gorge, with steeply rising heights on either side. Here and there the strip of lower ground is trenched and split by deep canyons. At first the rails follow the Mushkāf river, and the gradients are not very severe, but once Hirok, at the source of the Bolān river, is passed, a gradient of one in twenty-five begins, and two powerful engines are required to drag the train up. The steep bounding ridges now close in on either side, with cliffs rising almost perpendicularly to several hundred feet. Occasional blockhouses high up amid the crags defend the pass.