Voie du Pilier, the pillar route, is considered to be the less difficult of the two routes through the Petit Moléson north face. I cannot really confirm this, for me it appeared much more strenuous, mostly due to the fact, that once on the "pillar" - rather the north-eastern edge of Petit Moleson - the route stays vertical and doesn't relent until it almost reaches the top traverse. This traverse, however, follows a well trodden ledge and offers no difficulties, most likely the reason for the K 3/4 rating of the route. Anyway, I did this route on the same day after Voie Hohl and my batteries were running low already.
Voie du Pilier runs across the opposite side of the Petit Moléson north face than Voie Hohl and thus offers quite different aspects. The itinerary is similar, though less complicated: a traverse at the bottom, a very long vertical section, an even larger traverse at the top, a short vertical exit section and a short scramble and top out 15m from the summit of Petit Moléson.
Looking across the Moléson ridge towards Lac Leman
See the main page for the itinerary. Both ferratas start at the middle station of the Moléson cable-car on the Plan-Francey plateau. There is a restaurant on top of the mountain and another at its base at Plan-Francey so that you don't have to be afraid of starving.
Effort: 1100m length, 520m elevation gain, 400m gain on the pillar an the east face
Power: 5 - Extremely Strenuous, Crux in overhanging section at the end
Psyche: 5 - Plain vertical face
Difficulty: 3 - Medium for a ferrata but tricky in some of the sections, rated K 3/4 (6 is most difficult)
Orientation: 1 - There is no option to lose your way - follow the cable
The route starts at the cable-car station in Plan-Francey (where I assume you have to pay the 4€ fee - never did it myself) with a hike down to the bottom of the face. Passing a cattle fence the ferrata access trail turns off to the right (sign) and now heads up steep grass slopes beneath pine and fir trees. Take care in wet conditions as the slope is extremely slippery. In my eyes this is one of the two most dangerous sections of the whole route.
After 100m elevation gain you reach the first protected section, a warm-up across the side of a boulder, after which the trail passes the next boulder in a typical dirt-and-cable section. Right above this boulder the two ferratas split: Voie Hohl, marked red, turns to the right while Voie du Pilier, marked red, heads straight up a first vertical section.
This short section poses no problems, neither do the short leftwards traverse or the second vertical section. They are well protected and not exposed. Now a long diagonal traverse starts. It follows a sort of ledge and here for the first time some of the footrests are missing, making this section more tricky than anything on the more difficult Voie Hohl. A short pull at the end of the traverse brings you to the pillar, the north-eastern edge of the mountain. Here a sign warns you that you are aat the point of no return. And believe me - you are!
From this point the route climbs the pillar more or less vertically without giving you so much as one resting place for the next 200 vertical metres. It is very demanding and clipping you biners takes the rest of your strength. A first vertical section turns right into a short but tricky traverse at the end of which you reach an intersection. Here a very difficult alternative route zigs for 20 overhanging metres to the right, then zags back to rejoin the main route. This latter route remains vertical and pulls up mainly on the eastern side of the pillar passing by the little of the greenery you can find on the face.
High on top of this vertical section there is a small gully, the first option to take a rest, after which some further 40m take you to a steeply sloped plateau, overgrown with fir trees. Follow the plateau to the top and you'll regain the rock, vertical at first, then a diagonal traverse to the right and another vertical section, in all some 50m elevation gain.
At the top you'll head out on the big ledge, which traverses Petit Moléson's east face. This section, though protected by a cable, is regular hiking ground and poses no problems. Footrests and handholds are luckily missing here. The ledge cuts down into a pronounced dell, then heads up again to head for the final vertical climb. A short 30m section heads up the top east face, plainly visible for anyone who rides the cable-car. People within ooh and aah a lot when they see ferratisti up there.
Like Voie Hohl, Voie du Pilier ends with its crux, an overhanging exit onto the upper east slopes of Petit Moléson. Once you negotiate it, all that remains is a 30m scramble to the north ridge and the final 15m to the summit. For the main summit you have to descend into a saddle, then steeply up the west slopes of the main summit. Even here the route is protected.
Panorama from the exit of Voie du Pilier
Helmet (though rockfall danger is comparatively low)
Ferrata set Y-rope with biners and a rope braking device
Water (I was parched by the time I had reached a quarter of the route)