The first day’s hike was straight south along the rail line. It got steeper as it went, until it began to push the limits of what nineteenth-century locomotive technology was really capable of. For the watershed of the Blue Fork was terminated, to the south and east, by a vaguely Cape Cod—shaped range of mountains: a beefy bicep projecting eastward from the Selkirks, and a bony forearm running generally north-south, eventually merging into a branch of the Purcells. They were traversing along the flank of the latter, gradually putting more and more vertical distance between themselves and the Blue Fork. The trail began going on little excursions, elbowing its way into mountain valleys to spring over tributaries, then feeling its way around projecting ridges that separated such valleys. As these became more precipitous, the builders had resorted to constructing trestles across the valleys and dynamiting short tunnels through the ridges, which must have been maddeningly difficult and insanely expensive at the time, but now provided the bikers and skiers who used the trail with amusing distractions.