Reversible ropeway to the ice cave

The increase in capacity resulting from electrification of the rack railway led to constant congestion on the narrow path leading to the ice cave. And so, 14 years after the creation of the ice cave, it was decided to install a ropeway from Montenvers down to a point near the entrance to the cave.

Along the moraine flanking the tongue of the glacier, the former ropeway construction company Câbles & Monorails Mancini of Grenoble erected a 350 m long single-line reversible with twin track ropes and a winch drive. The 45-passenger cabin, which was built by the Grenoble coach builders Belle-Clot, had a stepped floor to take account of the slope of the line and two hangers with two carriages each. With such a design, the installation was rightly known as the Funiculaire Aérien (aerial funicular). Due to the limited space in the area of the top station, the haul rope had to be deflected from there over a distance of about 20 m to a separate machine room housing the winch. The line, which reached the glacier tongue at the beginning of the operations in 1961, had two portal towers. At 450 pph, transport capacity soon proved inadequate, and in 1972 a new stepped-floor cabin for 70 persons was supplied by Belle-Clot as part of a refurbishment project. The two carriages were also modified, and the uphill carriage was retrofitted with track rope brakes. The result was an increase in rated transport capacity to 700 pph.

Gondola lift as replacement for the reversible

Although the Mer de Glace has been retreating in general for about 150 years now and has lost about two kilometers in length, there was a brief period of glacial advance in the 1980s. That posed a threat to the bottom station of the aerial ropeway. In addition, glacial movement led to the collapse of the bridge leading to the ice cave in 1987, killing three people and injuring a further 27. The response of the operating company was to build a new ropeway on a modified line.

The new 255 m long ropeway – an extremely compact solution designed by Denis Creissels’ DCSA consulting engineers – is a pulsed-movement gondola lift with four groups of two cabins each. For the underground vault drive in the top station of the new lift, it was possible to use the machine room of the old winch-operated ropeway. The bottom station, with the return sheave and rope tensioning, is located on a steep rocky slope. Maximum gradient of the liftline is 120% (50º). The carriers are CWA Beta Vista cabins for 15 standing passengers.

In the stations, two gondolas stop simultaneously for loading/unloading in front of the drive and return sheaves, while the other two pairs of gondolas wait in the middle of the line. For optimized passenger flows, the cabins have doors on both sides. In the top station, the platform gate automatically opens for the arrival of the cabins and then closes again before the cabin doors open. This is a space-saving solution that makes the platform area under the downhill liftline available for passenger unloading.

In 1993 the Montenvers rack railway switched to year-round operation following the completion of avalanche protection works above the line. On their return from the 22 km long ski tour to the Aiguille du Midi via the Vallée Blanche and Mer de Glace, the world’s longest back-country ski route with ropeway access, skiers can also use the pulsed-movement gondola lift to return to the top station of the rack railway in winter, when it operates with two groups of cabins.